Same as Sagaths' topic a few down, i've had a similar starting problem. 

95 venge, manual. No history or lead up to these problems, I just went outside one night (maybe a few hours after the last time i drove it) and went to start it and the no go.  The dash lights were extremely dim but the deck, all my amps and all my subs/speakers got power.  I turn the key back to off and back to start many times and just as i'm about to give up all my dash lights get full power again and the car starts, barely, and i have to rev it up for a second for the battery to recharge a bit then it's fine.

This happened twice about a week apart, the second time I had to try more times and once I got my dash lights at full brightness the engine still wouldn't start (I did hear the relay click) and a few tries after that the car did start.  Since then I've done some work and took the battery + off but not the neg... both looked fine but I wasn't really checking for corrosion.  Both times were at night after about 4-5 hours of sitting.

Everything has worked fine the last few days but I don't want this thing leaving me or my girlfriend stranded somewhere.

Any ideas?

Thx

The starter would not turn the alternator enough to charge the battery, it draws more than the alternator puts out while trying to start the vehicle.

Is it turning over or just clicking?

Try turning off your amp and stereo, they may be drawing too much power and your starting circuit is not getting enough.  Other than that try cleaning the battery clamps anyway, check all your connections.  You might take it and get the charging system tested, or just the battery.  That would be the best place to start.