I'm in a similar situation, haven't rode since November and am just about able to ride a bike normally again now, so it could be worse
When I couldn't ride I pretty much watched movie and played my x-box more, but I always feel like I've wasted a day if I haven't got out of the house (school/ work doesn't count). I started just walking my dog a lot but it gets boring, and that's probably not relevant to you anyway. Tried to get interested in some photography stuff which is still kind of lasting, organised a fairly big Jubilee barbeque thing which took up a lot of time and plus I felt that was a decent use of my time. Read some books, build a model rocket (not for me though, don't find them interesting either) and got up to some other little projects.
Basically I've been filling my time with the stuff I wouldn't have done when I could ride, if there's something you thought about doing before your injury, do it now.