I try to give my snakes a lot of different stimuli. They are always curious about cameras, camcorders, a glass of water, just about anything catches their attention. I've found they are calmer when they get to checkout more items. Ignoring things I put in a second time. They probably remember it by sight and smell and feel no need to investigate. I'm up to 10 items with one group.
Today, I put some crushed ice in a small water dish. I thought it would be interesting to see how they reacted to such a cold item.
A couple came out but most just smelled it from the hide.