I have always wanted to take a vacation by myself. I have been curious about what you would do, could I stand the solitude, etc. Some things I thought about doing:

Hiking - going somewhere where you wouldn't see anyone else for a couple of days, no human contact whatsoever.
Drive across America - taking a long car trip, even though we did this every summer as a kid. Going somewhere I've never been (see Wednesday's post) like New England or Washington DC.
Foreign country - this is interesting because you would be more isolated than somewhere in the States, especially if it is a non-English speaking country. First choices would be Asia and Europe, although Antarctica is one of my ultimate goals. Mexico would be an inexpensive compromise.

I think I'm going to try to go in April.

Late.