They handed me a contract with an IP clause that summed up to their owned any idea I came up with. This wasn't uncommon at the time, but it was more aggressive than I was used to. I made it clear to the HR person that I was actively contributing to open source tools at the time, such as snort, nessus, and also had ideas of my own that I was already working on.
The HR person made it clear that if I were to continue working on these ideas it would become property of the company -- Even if performed during my free time.
I don't remember the specifics any more, but after some discussion and escalations we came to the agreement that since my hobbies were so close to my work function that any new ideas I came up with were property of the company, so I was asked to provide a list of what I was working on and it would be amended to the contract. I provided a 4 page outline of the 4 projects I was working on and their what intellectual property they involved.
The the next day they rescinded the offer. At the time I had assumed it was because their ideas were not that novel and they wanted fresh ideas to take and profit off of. Will never know for sure, but they went out of business between 2001/2002.
Regardless how right I was, since then I was always a lot more aware of IP clauses in contracts and how they were phrased. I also try not to work for companies who sell security software.