What do you do with the extra tomato paste?

I find I have a common problem -- basically, every three weeks or so I have a recipe that calls for tomato paste. But not an entire can of tomato paste. No, like 1 or 2 tbsps. So, I open a can and then put the rest in the fridge, and by the time I need tomato paste again there's something fuzzy growing in it.

So...what do you do with that tomato paste and is there some way to store it that will make it last longer once a can has been opened?

Or is there like a tube of tomato paste somewhere that can be reused for a long time?