You could do nosework, that's fairly easy to teach and do at home. Other suggestions could be frisbee, or you could create your own canine freestyle routine! All of Danielle's suggestions are great too!
Great suggestions above. You can order agility equipment online, or make your own - it may not be perfect, but just make it to fit your needs (or order a couple pieces and make a couple pieces) - and have fun with your dog. Watch some videos (if you're not an agility person) and then just go have a blast! No rules, no competition, but who cares? You can play your own nosework games (I just saw a great video last night, I'll find it and post it - it wasn't the sport of "Nosework" but nosework games) and dogs love using their nose. I do Nosework with mine (take classes and do it competitively for 3+ years), but also just ordered a tracking book and may start teaching mine tracking on my own just for fun. Anytime dogs use their nose they are doing what comes naturally, they're having fun, and you learn so much by watching them. If you like to dance, musical freestyle is another good suggestion. You don't have to do anything competitively - just do it for fun. You can watch some freestyle videos on Youtube if you need ideas, and then just have fun with a favorite song and your dog. I took a class a few years ago, and they had us start by trying several songs out, walking with our dogs on-leash and keeping time to the music while walking, and watching our dog - and sure enough, there would be song that our dog actually responded to, they'd get a certain "pep in their step", it was like they said "yeah, I like that song!" - find "your song" and figure out a routine (trust me, that "routine" part is much easier said than done!!! .
So much you can do -- just go have a blast with you dog!!