What should I do with a pound of Serrano peppers!?

When I have too many hot peppers like serrano or jalapeno, I chop them and freeze the for seasoning when I just need a little heat. Just wrap them tightly before freezing.

I like to pickle them: http://www.food52.com/recipes/616_pickled_green_chiles

I've never actually processed these to make them shelf-stable (though I'm pretty sure there are recipes here for doing so), but these last in the fridge for quite a long time, and are very welcome in the middle of winter!

That's a lot of peppers. You can make salsa but it will be really hot if you use a lot of them. Salsa Verde is easy to make, you just need access to fresh or canned tomatillas.

One thing that came to mind is infused oil or vinegar. Perhaps you can give some to friends. Here's vinegar from The China Moon Cafe Cookbook:

3 cups unseasoned rice vinegar (Marukan green label, or Mitsukan)
1/2 cup quarter sized fresh ginger coins, smashed
1 fat or 2 thin stalks lemongrass, smashed then sliced into 1/2 inch lengths
6 green and/or red serrano chiles. Store in extremely clean jar or bottle, strained or not, but don't press down if you do strain. If it clouds the flavor will still be fine.

combine in pot and bring to a simmer, remove from heat and cool

You don't have to worry so much about safety with vinegar like you do with oil because of the acidity. Here's some tips:
http://www.ext.colostate.edu/pubs/foodnut/09340.html