Pretty much the run of the mill employment contract will claim ownership of an employees creations, most regardless of whether that creation has anything to do with their every day activities. Some go so far as to claim all creations related to their discipline, even if conducted outside work hours.
The problem is simply that its too hard to challenge if such an issue ever arose. Any decent business wouldn't just claim everything under the sun. It is a worrying grey area though.
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).
The problem is simply that its too hard to challenge if such an issue ever arose. Any decent business wouldn't just claim everything under the sun. It is a worrying grey area though.