I suppose I'll do a spud gun showcase. Go to www.spudfiles.com for all your spud gun planning needs.
Specs:
6' barrel
16" combustion chamber
2 spark bbq ignition
.8:1 C:B ratio
Metered Propane fueled
10 seconds of airtime shooting straight up on an average shot
Cost about 65 dollars for gun and meter
Not very accurate
Towers 7 1/2' tall