As long as it doesn't conflic with ya job, like if ya actually do work 2 gether, same department etc....
I know a few people who met at work and dated and are married. To me it depends on the maturity of the two individuals. If the two are mature enough to just move on if it doesn't work out, then I don't see an issue with it.
I have, but only did it once and we went out. It was very nice time, we had.
In today's work place, not too sure, if I would ever attempt again.
I have done this more than one time and I do NOT reccommend doing it.
There are many reasons why but the main one is that if/when things go bad your job will no longer be comfortable.