As you may know, Richard Wagner turns 200 on 22 May 2013. Whatever you may think of the man (and opinion seems to diverge only as to which of his many character flaws was most loathsome), he is one of the most influential figures in the history of classical music.
I'm sure you are all looking for something to play to mark this milestone.
There is a relatively small body of solo piano music by him (Dover publishes quite a good complete collection) of which his Grosse Sonate is probably the highlight.
There are also a number of exceptionally good transcriptions of his (more important) operatic works. Most famous of these are the Liszt transcriptions, but there are also remarkably good ones by Carl Tausig, Glen Gould and Louis Brassin. The Tausig and Brassin ones are on IMSLP, the Gould one's are still copyright and in print.
If anyone knows of any more, I'd be most pleased to hear about them.