Every year (well, at least for the past 4 years that we have been going to it), the Cabela's closest to us offers a Family Fishing Day that includes fishing in their ponds to catch fish and if you get a tagged one you get a big prize (we've never gotten a tagged fish) and there are generally a couple other activities. This year the only other activity was BB Gun practice. All kids also go their own Cabela's Fishing Pole for free as well.
If you are local to me, you should try to remember to look for this next spring. They typically do it during the weekend before fishing opener. You will be all set with your family (after you go buy licenses for adults) to go fishing right when the season starts! Cabela's offers a variety of free classes throughout the year for adults as well as kids events, just check out the events on their website for the one closest to you.