I got my first flat in five months tonight (or Sunday, depending on how you look at it). I had the road bike out on Sunday then hung it up without noticing a problem. When I grabbed it for an evening ride tonight the rear tire was at about 25 psi. Stupidly, I just pumped it up and hit the road. I didn't have a lot of time before having to pick my daughters up at Girl Scouts, but I thought I could squeeze in a quick ride. Seven miles into a planned 8 mile ride the rear tire was completely flat. Naturally I didn't bring a spare tube, so I got to jog the last mile.

My lesson: slow leaks can quickly become fast leaks when re-inflated.