A wonderful indoor large group summer camp game is Captain’s Coming. Here are some of the commands – a la Camp Sertoma Version.
captain coming (attention salute)
at ease (stop saluting)
bicycle (legs in air bicycling)
all clear (stand up after hit the deck)
abandon ship (sit in rows of 3 and row)
return to ship (after abandon ship)
Chow Time (1 person pretends to be a table, 2 people pretend like they are eating soup)
hit the deck (lay down on stomach)
swob the deck (mop)
If you move without saying at ease or return to ship you’re out.
Another version can be found at TeamPedia.