This one I found on Cooks.com:
10 Chinese dried mushrooms, soaked in warm water for 30 min.
4 cups water
3 leeks, cut into strips (or 2 cans bamboo shoots, drained)
1 lb. tofu, cut into cubes
1 Tablespoon fresh ginger
2 cups bean sprouts
1/2 tsp. Tabasco hot sauce
2 Tbsp. cider vinegar
1/4 teaspoon black pepper
2 Tbsp. cornstarch
2 Tbsp. soy sauce
2 scallions, minced
Drain mushrooms, reserving liquid. Cut mushrooms into strips. Pour water and mushroom liquid into a saucepan. Add leeks (or bamboo shoots), bean curd, ginger, bean sprouts, Tabasco, venegar, pepper. Bring to a boil. In a cup, dilute the corstarch with a little of the soup liquid and soy sauce. Stir into the saucepan and cook for 2 minutes until soup thickens. Sprinkle with scallions and serve. Add slices of radish, carrot, or cucumber to garnish.
I haven't tried any hot & sour recipes yet b/c I'm the only in the house that would eat it. But I have looked at a lot of recipes and fantasized! Other ingredients that might work as additions or substitutions are chili paste, rice wine vinegar, chopped water chestnuts, chili oil, and sesame oil.
Let me know what you discover in your hot & sour experiments!