I found that my boys like to swim into something, a tunnel or pretty much anything creative. I made little planters useing a clear plastic party cup, added a little gravel to the bottom of it and planted an Lovelia Cardinalis, it looks like a little aquatic tree basically. Anyways what i found it my betta will swim into the cup where he's under the leafs but can swim around the trunk of the plant, kind of like a little hideing spot, not to mention the plants help clean the water. I also made a second planter and took a bunch of java moss and made a big cozy bed for my boys, at night I can find both of them (in their seperate tanks!) sleeping on their java moss beds, plus java moss is very easy to keep, doesnt need expensive lights, special water, or specific water temps. I got some for just 2 bucks =)
Oh and the floating ball thing is cool, like little soccer players
My two betta tanks are close to my community tank and I find that my boys will watch the other fish in their tank, kinda like their own 24 hour tv. Actually one day I needed to really scrub out one of my betta tanks cause I tried useing some fertaliser and caused a huge alge bloom, so i started taking water out of the tank and my betta swam into his cup. I took his cup and put him in my community tank where he swam around to meet his next door neighbors. I wasnt worried since theres nothing aggressive in my community tank and it was only going to be for a little while, nothing unattended. He just took it in stride, went straight to the bottom the tank and examined all the different plants and mosses I have growing in the tank. The other fish didnt mind him and he didnt flare at anyone either, hes the calmest betta i've ever had though. When i finished cleaning his tank and filling it with aged water that was heated to the same temp as my community tank I just reached in the big tank to get his potted plant and he came rushing to it and just swam into the cup! so i just lifted it back out and put him back in his own tank. They're smart fish and I think they appreciate fun things to do more than some other fish so be creative!
sorry for the long answer lol