The Third Age Trust has recognised the wide range of topics covered by Shared Learning Projects and U3A Research Projects and has set up a website where details of them all can be found. It might give you some ideas.
If you know of other work which should be included, or can add information to what is listed, please let Sheila Magee know about it (firstname.lastname@example.org).
The website is http://u3aresearch.co.uk/ . Click on Browse, then Northern Ireland to see what we have done.