The ticket office (closed when I was going back, on my picture) offered limited choice of post-Soviet items. I could find more choice around the parking lot earlier. But there were NO authentic post-Soviet items. Instead there were a lot of copies of Soviet pictures, banners, slogans put on mugs, glasses, plates, posters etc.
Unique Suggestions: At least some items were funny.
Well, good laugh was the best way to save common sense in the world of pure absurd during communist rules in my country, Poland. Immigration to the magical West or... schizophrenia was an option.
Fun Alternatives: Window shopping maybe a great fun as well.
The mini-zoo put in the Grutas Park was small, messed and very badly signed. I could see only birds there (+ a few rabbits). There was no information about the birds except short name of each bird species in Lithuanian and Latim language.
Unique Suggestions: Pass by...
Fun Alternatives: Generally I don't like any ZOO. The only ZOO I liked was in San Diego, California. Welcome :-).
I was very dissapointed to see only 2 small and useless leaflets on the Grutas Park at the ticket office instead of great bookstore with huge variety of simple and real historical books on Soviet era which involved over half of our globe in not so old past.
Additionally these useless leaflets were sold for 5.00 Lt as I remember. This one (8 pages) on my picture included only very short, basic info (in English, German, Polish and Russian) and even didn't include the map of the park.
Unique Suggestions: Don't buy the leaflets on Grutas Park at the place. Well, I bought this one, on my picture, more as a kind of souvenir than as a source of any usuful or interesting information.
Fun Alternatives: Look for info at official webpage of Grutas Park available in English, Lithuanian, Polish and Russian.
Print out the map of the park from here and take it with you.