You should probably have a tax professional help you with that (generally advisable when doing corporation returns, even if its a small S corp with a single shareholder).
Some of it may be deductible, depending on the tax-exemption status of the recipients. Some may be deductible as business expenses.
To address Chris's comment:
Generally you can deduct as a business on your 1120S anything that is necessary and ordinary for your business. Charitable deductions flow through to your personal 1040, so Colin's reference to pub 526 is the right place to look at (if it was a C-corp, it might be different).
Advertisement costs is a necessary and ordinary expense for any business, but you need to look at the essence of the transaction. Did you expect the sponsorship to provide you any new clients? Did you anticipate additional exposure to the potential customers? Was the investment (80 hours of your work) similar to the costs of paid advertisement for the same audience? If so - it is probably a business expense. While you can't deduct the time on its own, you can deduct the salary you paid yourself for working on this, materials, attributed depreciation, etc. If you can't justify it as advertisement, then its a donation, and then you cannot deduct it (because you did receive something in return). It might not be allowed as a business expense, and you might be required to consider it as "personal use", i.e.: salary.