40 liters, what to do!?

hello once again all,

here is the deal.... i have recently taken down my sump, a 40 liter (10.5 gallon) rectangular tank.

now what would you do with it? here are my thoughts,

a QT/hospital tank, would this be a large enough volume for this?

a planted fresh water tank (i have a 20 liter one for my betta and it looks really cool, but yea i already have one)

use it to farm some sort of live food for my 120 gallon

and finally the more daring option, turn it into a miniminimini reef tank, would this be possible? what could i possibly keep in a 10 gallon? i have two yellow tale blue damsels as some of you may know that i fear to add to my 450 liter as they will most probably create havoc, you think they will get along in a 10 gallon (personally highly doubt it)

 

Do this... http://www.3reef.com/forums/show-off-your-fish-tanks/update-pic-my-10gal-nano-reef-130675.html