PG used to play squash. If you ever get a chance, ask him to tell the hilarious story about how it nearly got him kicked out of the Army.
I think Simone Niggli used to play squash once a week during the winter for cross training! I played in high school and undergrad and really enjoyed it. You got what we call the tour de court :)
I used to play basketball once a week one winter in the 80ies. This basically turned into an interval session running up and down the court for 2 hours straight. Definitely showed at the beginning of O season and I didn´t seem to get tired at all in the long runs.