I got to see Red Skelton once,
on what turned out to be his last tour... 1991 or '92, I forget the exact date, but it was during the first Gulf War.
In spite of his age (he must have been close to 80), his timing was as sharp as ever, and he did a lot of his classic routines like Gertrude & Heathcliff, the Mean Widdle Kid, and (my favorite), Guzzler's Gin.
Speaking of his timing, he actually made a joke about it, and his age. At one point, he stopped right in the middle of a gag, like he'd lost his place... then, after about ten seconds of silence, he said, "Bet you thought I was senile, didn't you?" and finished the gag. This brought down the house.
R.I.P. Red, you were one of the all-time greats.