I have had a few on UA over the years due to traffic ahead taking too long to leave the runway. Nothing major, just a rise in power and a smooth climb (plus a 30 minute delay at airports like DEN as you try and get back into the queue even with an expedited approach).

I have seen a simultaneous aborted landing and rejected take-off at SAN back in the 1970s. One Western 727 was on final and another Western 727 just motored onto the active and started her roll. She rejected almost immediately and the other one aborted her approach. Likely looked closer then it was, but since I was maybe a few hundred meters away (in the observation area parking lot at the end of the runway) it was a heart-pounding moment.