Holiday Party Planning with no budget

I have been asked to plan our team's holiday lunch and team building activity, and I am stuck.

There is no company budget, so each person must pay for themselves. The team consists of 20 people, mostly ages 40-60, 80% introverts, average American fitness levels, all born and raised in standard Midwestern US city.

What are some ideas that 1) Don't cost a lot of money, 2) would be appealing to this demographic, 3) can take place during the workday, and 4) can be done indoors due to the winter weather?

Personally, I hate the idea of forced fun, so I want this to be as quick and painless for people as possible while still checking the box for a successful holiday lunch/activity. I'm open to any suggestions!