Do the little library thing that's all the craze now
What is that?
Its where you build an enclosure to house some books and erect the "Little Library" somewhere that people can come and engage in a "Take a book, leave a book" exchange. That really would probably fall under "fun projects" more than any lasting volunteering opportunity.

As far as helping the elderly with computer problems, its not as bad as it sounds. Yes, troubleshooting someone else computer issues is a nightmare, no mater how old they are but theres other computer use things they need help with that aren't so bad. When i was in high school, to get some extra volunteering hours i taught classes on computer literacy at the local senior center for a few months. It was a neat experience, there were a couple of folks who got some real use out of it, but the majority of the people were there just to get out and socialize.