No mention of Personal Best yet. Excellent movie in my opinion. Written by Robert Towne if I remember rightly (who also wrote Chinatown). Homophobes beware, though; here there be lesbians.
I'll add votes for Rocky and North Dallas Forty as serious movies about sports.
For comedies about sports, I'll go with Breaking Away and Semi-Tough.
Being older, I would include:
Damn Yankees - musical with Ray Walston and Gwen Verdon
Pride of the Yankees
Alibi Ike with Joe E Brown
Angels in the Outfield
Fear Strikes Out, about Jimmy Piersall
Kill the Umpire
SMB 60-64, Alumni Marching and Concert bands, Kalamazoo Concert Band,71-present.
Three best sports movies