In Texas, we have lots of Computer Science contests – Texas CS Contest List.  I find contests very worthwhile and fun.  My students typically feel the same way.  We typically attend 8 – 10 contests per year and host a contest at my high school in the spring.  If you are looking for a way to get more students excited about Computer Science, consider hosting a contest and getting other area schools to do the same.  I have found contests to be a very quick way to boost enrollment, especially once you establish a winning tradition.  All students want to be a part of a winner! Once you get a few contests or even a single contest going, other schools will join in and before you know it there will be more contests than you will have time to attend.  A typical Saturday contest in the Houston area would have around 80 teams of 3 students with 15-20 different schools attending.
The UIL Computer Science Contest is a state-wide contest run by the University Interscholastic League.
This Texas-based contest is very well done and would be a great model for any state wanting to get contests going.