As part of it's 1-1-1 Philanthropic Model, Salesforce encourages it's workforce to spend at least 56 hours per year on volunteer projects. These can be anything you choose - from volunteering IT skills through to picking up litter or packing peas. I've done all three and each is rewarding!
I recently spent time with a group of Salesforce pros to build a web application for a US based non-profit. I had no affiliation with this non-profit before volunteering.
It was a great opportunity to dust off the coding 'skills' and work with a new group of people across a few different timezones, as well as meet an interesting set of customers with needs to be met. Understanding their business and in turn their customers really helps expand the mind about how non-profits operate and the gaps that they fill.
Details of the application we built are here.
Adopting the 1:1:1 model really encourages the workforce to donate time that they might not otherwise find - so I'd really recommend that companies from small to large consider adopting Pledge 1% Percent.