I wash or at least wet my hair every night, flip my head over, scrunch some gel into it, then scrunch it up into a semi-messy bun.
The reason I do this is because I have really long (half-way down my back) thin hair that frizzes really bad when it dries. Plus, if I try to let it dry down, it doesn't curl as much (i think it is partly due to gravity or something).
So sleeping with my hair in a bun lets it dry in curls, and helps cut down on frizz.
In the morning I let it down and crunch a little more gel into it