Ones that happened recently (in the last 6 months):
I bought the Samba de Amigo maracca set (in a perfect looking box) and inside it was not only CIB but it had the game -mint- inside as well.
And I bought SSBM used and inside was a 251 memory card.
Some time ago, found about $2.80some in loose change at the bottom of this trash bag that I had to go throw out. There was more, but I didn't bother.
That and once found a copy of Street Fighter the Movie game for the Saturn CIB with a copy of Fighting Vipers inside. Bought it, even though I already had SFtM, but that was a disc-only affair.
I bought Shenmue 2 used at Game Crazy a while back. I was driving back to my house and I realized there were two disc in it. I was Shenmue the movie. I really didn't expect them to give me the movie also.
A year ago, I bought a Saturn Netlink for $30 off eBay. When I got it, It came with a sealed-in-wrap, about new, Sega Saturn Model 1! Had everything (Controller, Paperwork, Cardboard) Also, the netlink was in the same condition. The seller also thew in the Saturn-to-PS2 (Keyboard) converter with a rockin' Sega Branded Keyboard! My best score Ever! Sadly, I never use the thing. I have no software and I'm always broke! It just sits on my display next to my xbox media center!
Ottobot hit me up with a free Ikaruga ( not an actual store bought disc, but still) inside his dreamcast he sold me a while back. Not that the friend I bought it for would ever have the coordination required to play the game, but still, pretty awesome bonus.
Don't that just look oh so tasty?
NES-GB-GENESIS-SNES-GBC-32X-SATURN-3DO-N64-DREAMCAST-GBA-PS2-XBOX-GAMECUBE-DS-PSP-WII-360
I bought a huge lot of old video game stuff from craigslist in April. It was a ton of stuff, Atari 2600, 5200, 7800, NES, SNES, SMS, Vectrex, tons of games, over 350 Atari 2600 games, around 250 unique titles. etc. etc.
Anyway I get there and the guy tells me he found a Fairchild F System he forgot to put in the listing. So he just threw it in for free. I had never heard of it, but it turns out that this is the very first game console with removable cartridges. It's barely more advanced than a pong console, but still a pretty remarkable piece of gaming history. I got about 8 games in boxes with instructions with it.
Oh yeah, there was also an Amiga joyboard (with Mogul Maniac) in the lot. SMS 3d glasses, most of the 3d games. He also had a big box of game manuals, advertising material, etc, I sorted through that and found a ton of Intellivision controller overlays in immaculate condition. That lot was really a steal.
We are prepared to live in the plain and die in the plain!