Well in the contract with my current employer, it pretty much states that every IP I create during my employment belongs to my employer.
So if I wanted to create a project that I own, I would have to terminate my contract first. This is especially annoying being a Student and having many ideas all the time. Oh well.
Speak to them and get an exemption, even on a case-by-case basis. Those ideas need to not die out, and you might find that being able to give life to them makes you simply a better employee.
Unless an employee contract says otherwise, the default copyright position is that all work done is part of "work-for-hire".[1] There are a few reasons for this, and Joel Spolsky covered them pretty well.[2]
Every employment contract I have had (I'm not in the US and, I think, neither is crazysaem) has had rather a lot to say about copyright and IP - not all of which might be enforceable in a court (I have had lawyers look at contracts).
