It was always an issue for us too, especially with the seniors who aren't planning to cheer in college. Lots of "why do we need to learn new stunts" or "we don't need team building stuff planned, its going to be a new team in 2 months". Setting an achievable but challenging goal for the semester can change the pace from monotonous basketball season to working towards something again. Maybe have the girls set their own goal to do a service project of their choice, work with pee wee teams, or get _____ number of people to big basketball games. It keeps them involved, but in a different way than competition and football season.
At my school, we focused on getting the school more involved and hyped up for basketball season(which isn't so popular here) and also focused on giving back to the community. This way, it wasn't so much of a comparison between football season and basketball season (with the unanimous "basketball is boring! Football season is SO much better"), but more of a contrast between the two. We still tumbled, stunted and conditioned of course, but practice was definitely more based on trying new things at practice, switching around stunt groups/stunt positions to strengthen our team's versatility and getting the community involved outside of practice. Also, setting little challenges during practice was always fun. Things like "make up the most creative prep level pyramid" or "create a routine" etc. etc. actually came up with some pretty good material and were fun. Overall, I really think service projects helped our team have fun but also work towards something that no matter if you are cheering next year or not, can focus on.