Here's my greenhouse:
As you can see, I have three wilting plants in my garden - the ones that I got wrong during my last study session - but I can water them (study some more) to make them healthy again.
It looks like Memrise started as a Chinese language study tool, but lots of other languages are available as well, including Spanish, Polish & Biblical Hebrew. You can even use it to increase your vocabulary in English so that you can finally ace the Sunday crossword puzzle.
I've been using Memrise while I'm at work to exercise my mind at the beginning of the day or when I need a short break from editing in the middle of the day. It's a great way to jump start my brain & much better for me than Angry Birds!