If you want to keep busy or interested, try a nano cube. That will keep you occupied, nothing like a little algae outbreak, or a cyno outbreak, to keep you busy.
You can add an HQI's and that will let you run into heat issues which will allowto buy a chiller and since you have the chiller you can add a HOT skimmer like AquaC makes.
After that you can figure you dont have enough flow-which could have been why you got the algae and/or cyno so you can add a few Koralia's which certainly will drive up your heat and justify the chiller for sure, and since you have the chiller you can easily justify the skimmer, and maybe the HQI's are to much so you can get a fixture that has 6-24wT5's.
Before you know it, it will be winter and the gloomy weather will have you all happy again, and glad you have a larger tank!!!
By the way, I have a 24 gallon Nano for sale, a 1/10hp chiller, an AquaC HOT skimmer, and a light fixture that houses 6 24 watt T5's plus a few Koralias for sale(wife)
another idea is to get a few real cool zoas, and make a LR colony out of multiple colors-and hey maybe that nano can be a frag tank(nono)(nono)(nono)(nono)
hind sight I tell myself hind sight(scary)
WOO HOO you gotta love this hobby!!!