Most time travel games are fairly disappointing, in that time travel is simply used as a mechanic to transport characters to the site of an adventure and back again. Most of them would work equally as well if you used alternate dimensions, or travel to another world, etc.
Some, though, allow you to play with affecting history via the game's mechanics. Sending messages to yourself, doubling yourself, etc. Those are the ones that are most interesting to play.
Time & Temp succeeds admirably with an interesting mechanic, but it won't be for everyone.
Brown Chronometric Engineering, Inc. maintains the integrity of the time stream by sending teams of troubleshooters into the past and future to correct any possible paradoxes. Successfully creating a paradox would unravel all of reality, so is to be avoided.
Unfortunately, the simple presence of an individual in another time can cause unintentional changes in the timeline. The more capable and important that individual is, the more they change time simply by existing somewhen.
So while Brown Chronometric Engineering does recruit employees from all across history, they stay away from the famous or capable. Those sorts would do more harm than good.
Instead, they recruit the local equivalent of temporary office workers. People who can be relied upon to do the job, but not so capable or important as to warp history out of joint simply by being.
Time & Temp uses an abstract view of characters. To create a character, you write a cirriculum vitae (C.V.) for that character. This will include their last three jobs, each with two bullet points for related skills. There is some benefit to having a job that provides some leadership skills, to be able to coordinate multiple characters in a team effort.
For example, an entry might be:
Marching Band Instructor
-Teach musical techniques & theory
-Teach and coordinate marching
Later, when trying to do something that involved music, or coordinating group movement, this job would give the character a bonus.
Time & Temp offers a unique approach to resolving tasks. The player rolls a number of dice whose size will vary depending on what's being attempted and how significant its effects might be.
The number of dice rolled starts out at 1. If the GM or the player or any other player thinks that the character has a chance of failure, they roll an additional die. If anyone thinks that the character has a chance of incident, they roll another die (an incident means the task basically succeeds, but in such a way that puts the character at a disadvantage in future tasks). They might also roll a Paradox die if the effect of the task has a risk of causing paradox.
The player can always choose to have their character succeed at the task, regardless of the values on the dice. However, the player may very well choose to accept failure or incident in order to have less of an effect on the timeline (and thus less of a chance of creating a reality unraveling paradox).
To succeed, the player chooses the lowest die value out of all the dice. To fail or suffer incident, the player chooses the second lowest value (this may be the same as the lowest value, if more than one die rolled the same). To choos the third lowest value, the player must both fail and suffer incident.
Why choose numbers? The numbers chosen in task resolution get plugged into the Matrix.
The Matrix is a two dimensional grid of numbers that shows the effect the team has been having on the local timeline. The numbers fill in from the upper right, starting with the number chosen by the player who operated the time machine to travel to the destination time.
Forming different patterns in the matrix can have either bad or good effects.
The primary bad effect is if two numbers that are the same are placed next to each other. This creates an anomaly. The first one is good for the temps (deja vu allows them to reroll some of their dice), but future anomalies are generally bad. They represent other times leaking into the current one, increasing the risk of paradox.
Good effects come from forming more complex patterns in the Matrix. Nine unique numbes in a square, seven consecutive numbers in a row, etc. For each of these patterns you form, the team gets on Synchronicity token. These tokens can be used for various beneficial effects.
For example, a character can receive an email from the future giving them just the information they need, or they suddenly discover that one of the locals in the time is actually an ally, recruited by the character's future self. All the way up to the character's future self actually arriving to help out personally.
Think about the sorts of tricks Bill & Ted played to gain a temporal advantage, and you'll have the idea of how you can use Synchronicity tokens.
Time & Temp does a great job at what it sets out to do: providing a rollicking good time travel adventure where the characters can meet themselves, invent rock & roll, and various other things their bosses shouldn't find out about.
The game won't fly with all groups, though. There's nothing tactical about conflict resolution in the game and a player must choose to fail rather than have it thrust upon them by the dice.
But if you have a group that is willing and interested in playing with time, Time & Temp is well worth a try.
For a brief two-part example of play, head over to the author's website: Voyage of the Examplinauts.
You can also buy a PDF version of the game here: Time & Temp PDF.