The spacetubes.zip file you have requested: Maps Levels Missions / Space Tubes - 141.08kb is not available. Perhaps try browsing all files for the game Team Fortress Classic and upload any files you want to share or are missing. This is the only information we could locate:
Fight in a network of glass tubes. Get to the enemy base, hit the blast switch, and send them into space! Watch their bodies explode into little peices.