There's not that much that you can do with a sourdough starter. Of course, you can feed it and keep it as a kind of esoteric pet that you sometimes take parts of and make bread from. You can also use up the rest for more bread.
There is one more thing that I am reminded of though. In one of my cookbooks (Det naturliga köket by Mathias Dahlgren, the recipe is from one of his Michelin star restaurants serving mostly swedish-inspired food), there is a recipe for deep fried rye sourdough starter. Now, it's not just the starter, and it is for a rye starter, but if you're feeling adventurous it might be possible to substitute it with your whole wheat starter.
It's 1 liter of water, 600 grams of coarse rye flour, and 90 grams of rye sourdough. Mix the ingredients, and leave in room temperature for 6 hours. Put it in a pastry bag, and pipe medium strands into a 185°C deep fryer. Remove when golden brown and crispy. Toss with salt.
I do however doubt that you will find many other uses for a sourdough starter, other than to make bread.