I've got a 1993 Geo Tracker 4x4 convertible.  I usually leave the top off and don't drive it much during the winter.  I was out of the country during the entire month of January so it didn't even get stared while I was gone.  The day after I came home, the weather was reasonably warm enough to throw on a jacket and take a short ride.  Was afraid the battery might be dead, but it started up first try.  Drove the car to work the next day, again no problem starting, but the windshield seriously needed cleaning.  So the next day at lunch I thoroughly clean the windshield.  At one point I left the hose  laying on the area at the base of the windshield while i went to turn the hose off.  When I hopped in and turned the key, nothing happens.  No click, no attempt to turn over, nothing.  Tried several times, and nothing.  Went to work, expecting to work on the problem when I got home.  When I got home and tried it out, it started right up.  Ran perfectly for two days, then refused to start again.  It has been doing this now for over a week.  One day it'll run fine, but then every now and then it refuses to start.  15 minutes later, it'll start just fine.

Has anybody else ever had this happen?  Any ideas what it might be?

Sounds like a loose connection, or bad terminals to me.

Well, the problem seems to be centered around the solenoid activation signal wire.  (The small black and yellow wire that has a female blade connector on it that clips onto the blade terminal on the side of the solenoid.)  Taking that wire off and putting it back on a couple of times usually allows the tracker to start.

Over the weekend, I took the wire loose, hooked up my voltmeter to make sure it was getting full 12V(or 13.8V as the case may be) and it checked out.  I was alittle rough with the terminal when I reconnected the wire, and I think I bent it just a bit.  Anyway, now the tracker is starting ever time.  Sometimes these things get really finicky I guess.  The sad par is that I replaced the starter last year when it was doing something similar.  May have been the same wiring issue.