Super Duper Cheap Calls - Who Buys Them?

Sometimes I am holding a quiet underlying, and seeing "bid $.0 ask $.25" will step into the breach and offer some calls for five or ten cents. I figure "It's beer money". I know conceptually that no option is riskless. OK, there could be a ratings announcement on the underlying, or some exceptionally good quarter, or a technology breakthrough. But practically speaking, these are worthless options and they've always expired as such. Who buys these? Are there people with a little spare cash in their accounts who just wing it on a prayer? Maybe the market maker accumulates these - and figures despite the losses, across hundreds of securities a profit can be squeezed together?