Flash website: select a navigation button,a trapdoor opens and the button drops through and is left hanging. Added accompanying chain creaking sounds effects when the trap was reset and the button was "reeled" back onto the navigation area. The trap is reset, ready for it's next "criminal".

In case you're wondering, it's for a financial planning website. My team lead ultimately rejected the idea but not after a good chuckle 🤭

I also remember:

Geocities, tripod, Altavista, ask Jeeves, animated GIFs, yahoo, connecting with a 56k dialup that woke up the entire house, legendary Nokia 3310, ICQ, IRC, phpBB, Winamp: it really whips the llama's ass, Netscape navigator, Newgrounds, Homestar runner, everything Flash.