Love Lem, especially The Futurological Congress
Talk about mind bending.
By the way, there’s a movie somewhat based on it with Harvie Cartell. Worth a watch.
I'm really not a "the book is better than the movie" guy, but here I really think the movie isn't very good in comparison. It doesn't even have much to do with the book, and it loses all the intelligent humor of the original. The book is a very light short read and hilarious. The perfect introduction to Lem.