The Power of Two, and the Power of Two II, too.

1. Ian MacDonald (TMWKTL, Starman)
2. Gerrard (Pilot, BITH)
3. Mrs. Vecchio (Pilot, TEHDT)
4. Eric (Pilot, The Mask)
5. Victoria (Victoria's Secret, Letting Go)
6. Caroline Morgan (Free Willie, Vault)
7. Willie (Free Willie, The Wild Bunch)
8. Mackenzie King (DDO, One Good Man)
9. Warren Knoop, Mackenzie King's long-suffering boss (DDO, One Good Man)
10. Staff Sgt. Meers (Pilot, Victoria's Secret)
11. Rhonda (TMWKTL, Flashback)
12. Mrs. McGuffin (Chicago Holiday, Invitation to Romance)
13. Public Defender Williams (Free Willie, Heaven & Earth)
14. The bartender (Pilot, Manhunt)
15. Superintendent Moffat (Pilot, Invitation to Romance)
16. Jasmine (Invitation to Romance, Victoria's Secret)
17. Angie Vecchio (One Good Man, The Duel)
18. Damien Kowalski (Easy Money, Mojo Rising)
19. Frank Zuko (The Deal, Juliet is Bleeding)
20. Charlie (The Deal, Juliet is Bleeding)
21. Ante the Poodle (Odds, Good for the Soul)

1. Fraser played basketball
2. A carriage ride
3. Fraser blew Ray Vecchio's cover
4. Fraser played poker (and had trouble remembering the words "Full House")
5. Ray Vecchio nearly drowned
6. Ray Kowalski went swimming in Lake Michigan before he learned to swim
7. The Riv exploded
8. A vehicle was driven into Lake Michigan
9. An elderly man played chess
10. A recipe is a vital clue
11. Someone feigns death well enough to fool everybody
12. Camilla Scott sings
13. We see Dief in a cage
14. Mrs. Vecchio instructs one of her children (by phone) about purchasing groceries
15. An American cop wears a Mountie uniform
16. Fraser dances
17. Ray Vecchio has Dief on a leash

There are probably many, many more--but I'll leave that up to you. Have fun with it!