My very fave is Polly? Penny? from Noises Off... Which I've done a few times... Please read on for funny anecdote:
I was SMing Noises Off, and of course had a ridiculous and hideously large prompt book- and one day I was reading a note as I was walking into the rehearsal studio and, of course, tripped and the book literally went flying. It was terrifying and hilarious. There were pages everywhere... and it took me hours to get everyhting back together.
So, our actress added that "bit" to her character... as well as having a million pencils in her hair which is again me all over and soemthing I didn't notice she added until very far into the process, and also, as an homage to another friend on this network, wore a stopwatch around her neck.
Gotta love the Human Race!