I'll second the external service highlighted by "anon! anon!" and add some more items regarding internal service. This is especially important if you're at a smaller school compared to an R1-type place. (I did my grad work at an R1, and the faculty generally did as little "service" as possible; I've also been a VAP at two SLACs, and those places absolutely depend on everyone making some sort of contribution.)
Internal service - there are always going to be departmental committees, like setting up colloquia, determining the curriculum, advising undergraduate things like Psi Chi or the Psychology Club, possibly maintaining the department website, etc. However, this also includes advising undergrads, and serving on ad hoc search committees.
There's also the service that you may need to do for your institution, beyond the department. This includes positions like being on faculty council, the IRB committee, the tenure/promotion committee, advising student organizations, and being the outside person for search committees in other departments.
Again, the requirements are going to be WILDLY different depending on the school. Even so, I have had several senior people remind me that no one gets tenure because they're a service superstar …