Getting around in Karlsruhe is quite comfortable without a car, because most of the town is reachable by trams, tram-trains and busses. They pass very regular during business hours, also till late in the night (about 1AM/2AM, depending).
The trams, tram-trains and busses are managed by the Karlsruher Verkehrsverbund, so you can use them with the same kind of ticket. For knowing which ticket you have to buy there are plans with combs (German: Waben) how many combs you'd going to travel througth. The city of Karlsruhe counts two combs, so it costs 2 Euro for a “individual ticket” (German: Einzelfahrkarte) The “individual ticket” is valid 1.5 hours with changes, but only in one direction. There are also 24h tickets available valid for one (“Citykarte”) or five persons (“Citykarte plus”) for 4.50 € respectively 6.80 €. If you have planned more rides on different days it is recommend to buy a 4-pass ticket for 7.00 € allowing you to make four trips.
If the ticket has no date on it and a blank bar on the right, be sure to stamp it as soon as you enter the tram or bus, otherwise it is not valid. (Prices: October 2008)