My friends and I came up with an interesting way to play a Risk/Pandemic hybrid.
What you need: A copy of Risk and Pandemic. You will need the armies, dice, board, and cards from Risk and the Disease cubes and characters from Pandemic
Set Up: For starters, you are playing primarily Risk. The winner is whoever defeats their opponents and is the last man standing. You set up the board just like risk first, using the risk cards to place starting armies. Then, you put those cards back into the deck, shuffle, and draw cards to determine where disease cubes go, using Risk cards like the infection deck (Draw 3 and place 3 in those cities, then draw 3 and place 2 in those cities, etc.) Asia was one color, Australia and Africa were another color, then England and Greenland were the third color, and the rest of North America and South America was the fourth color. Each player gets to pick a character from Pandemic and place it in a region they control. You also use the Draw deck from Pandemic, but only to determine when an epidemic happens.
The Game: You play like Risk, building armies, attacking enemies, etc. but with one important caveat. if a city has a disease cube, the defending army acts as if they have 1 fewer unit there (so if an army is defending in greenland and they have 5 troops and 2 disease cubes, they act as if they only have 3 troops). At any point on your turn, you can activate your Pandemic meeple just like in pandemic, (In this version, ignore the dispatcher, scientist, and researcher).
It's still a little rusty, and some things need tweaking, but it was enjoyable. :)