Actually, I should say "lightsaber play" - this is what my boys do, endlessly (well, it seems that way sometimes anyhow). They make all those zooming lightsaber sounds, swing their arms in that lighsaber way, and somehow they manage to rarely actually hit each other, others, furniture, etc.
They've also gotten really good at being dead, and cutting off each other's arms, heads, etc. I'll hear, "Ohh, I'm dead!" or "I cut off your arm!" as often as I imagine young girls' mothers might hear, "Here's some more tea for you, Mrs. Tiddly-Wink!"
And while I am ambivalent about my 3 year-old playing at this kind of thing - so young and cute, he's practically a toddler! - I still allow it. I try to think of President Jimmy Carter, who as a boy played cowboys and indians - and ended up one of the world's greatest humanitarians. I think boys just need to do this, and to squash the impulse may mean denying them a whole part of their boyness.
It also may prevent opportunities for pro-social growth; today, while playing with some buddies in a particularly rough-and-tumble lightsaber battle, a pal got knocked down, and stayed down. Owen was one of the first in there asking, "hey, you okay?" (He was, he stayed down as part of the game.) I wonder, if we Moms had stopped the battling, if that moment and others like it may not have happened; I'm glad we were able to just let "boys be boys."