I haven't seen this anywhere else in sightings (I even used the almighty search).
In Tony Hawk's American Wasteland, go to the Vans Skatepark. Where there's the door that warps you to the top of the halfpipe, walk throught the white door on the right and throught the wall. Keep walking into the invisible wall until your skater starts moonwalking. Then walk outside beside the pool, and press X.
Your skater will shoot up and then teleport to the other side of the pool, and one of four messages will appear, "MSG'D!" "Arrowed!" "Children'd!" or "Late 360 Shove-It to Boneless'd!". Another cool effect of this is sometimes your board will disappear and you will be skating on thin air.
This is similar to the Homestar eggs in Tony Hawk's Underground.
Yeah, I didn't notice till recently, and I'm a huge Tony Hawk player.
Guaranteed Way To Get The Invisible Board Off This Glitch/Egg (But no Homestar message.) When you get to the moonwalky part of this egg, don't walk all the way out to the pool. Instead, walk just outside the wall facing the pool (so you're still underneath the ceiling outside the door.) Press X then to get a guaranteed invisible board (but you WILL NOT get the Homestar message.)