Time for a fun glitch to be exposed!
How to spawn camp on the mario kart map. Be engineer and have two partners.
Make one partner a Medic and then ask the other partner to join red as a demoman.
When the demoman makes it over run to the wall and have him shoot 8 stickies
Tell the medic to uber you and you will reach the roof
When on the roof build teleporters and wham you are spawncamping red