Even with modern graphics and complex sports simulation games, Backyard Baseball (specifically the 2001 version) remains a staple for several reasons:

For those who want a more stable experience than a browser site, the original game has seen a massive resurgence on modern platforms: ScummVM :: Forums How to play Backyard Baseball? - ScummVM :: Forums

MyAbandonware.com Version: Backyard Baseball (1997 – Original) File type: .exe + pre-configured DOSBox or ScummVM wrapper. No Flash? Yes – It’s a standalone executable. Hot factor: 100% original sound and speed.

Once you find an unblocked version, you'll want to win the championship. Here are some tips to dominate the Backyard League: Build the Perfect Lineup