Having not seen this movie in several years, I watched it this past week and was surprised to find not one, but two appearances by Neighborhood cast members. If you've never seen the movie, I won't spoil the plot for you -- but the plot involves the mob, deception, and a lot of get-rich-quick themes.
The mob boss in the movie is Happy Marcelli -- played by none other than Don Brockett.
A quick search online reveals that just six months after the release of Houseguest, Mr. Brockett died of a heart attack at the age of 65.
With a closer look at the movie (after a glance at the credits), there's another Neighbor who shows up in this movie set in Pittsburgh. Again, I won't spoil the plot of the movie but there is a televised lottery show in the movie called the Big Spin. The host of the Big Spin is played by Chuck Aber.
Silence of the Lambs, Zack and Miri...Neighbors tend to show up when you're least expecting it.