Soccer: See if there is a Minnesota United FC game during his visit.

Related to walking, introversion. and possibly bookworminess: Visit Fort Snelling, and/or take a hike along the trails in Fort Snelling State Park. This is where the Mississippi and Minnesota Rivers meet. There are big trees and plants that smell good and pretty scenery; a Texan who enjoys walking might find it a little fun and different from the environment he's used to.

If a good-ol'-fashioned walk sounds good, then you have many options. There are probably great parks and trails close to wherever you're living. The Eloise Butler Wildflower Garden and Bird Sanctuary, for example, is one of my favorite places to go for a walk in the Twin Cities. It's small but oh so peaceful and pleasant, and also not overly popular, which helps with the peacefulness.

Out of comfort zone/ just throwing it out there: Maybe an improv comedy show at Huge theatre? They have some very funny people. And in my experience, people tend to have a great time when they see good improv comedy, even of they aren't normally way "into" that sort of thing. There is excellent bonding potential in simply having a laugh.

Hope you guys have fun!