I grew up watching TV shows like MacGyver. On the episode Ghost Ship, the girl in distress is played by Katey Wright. On that episode she's Russian. Then, a year after on the episode Collision Course, she playes an American character. Donno if as a kid I noticed them recycling actors, because she wasn't the only actor to play more than one character. Kai Wulff played four different characters. Heck, even Dana Elcar played two characters: normally he was Pete Thornton, but on the pilot he's Andy Colson. Maybe someday I'll try and see how many actors they recycled, and how many actors have appeared on both MacGyver and Stargate SG-1. Heh, Katey Wright has appeared on both :)

Update:

A list of actors who have played more than one character on MacGyver. Actors who have also appeared in Stargate SG-1 are in italics.

	Actor	Characters
1.	Gregory Sierra	Captain Diaz, General Antonio Vasquez, Colonel Antunnez
2.	Bill Croft	Tansey, Max, Rote, Donnelly
3.	John Considine	Sandler, Andrew Lawton, Foxworth
4.	Michael Constantine	Sam Leland, Jan Messic
5.	Richard Romanus	James Crowe, Joey Bennett
6.	Joseph Lambie	Eric Woodman, Andrew Harryman
7.	Tia Carrere	Tiu, Lisa Chan
8.	Robin Mossley	Earl, Wrigley, Alexander Shannon, Charity Santa Claus, Wilt Bozer
9.	Anthony Pena	Elias, Hector Lopez
10.	Jay Brazeau	Zamora, Phelps
11.	Anthony Stamboulieh	Hakim, Ambassador Vulnay
12.	Clyde Kusatsu	Anek, Sam
13.	Kim Miyori	Tara, Dr. Triwai
14.	Frank C. Turner	Unknown, Priest, News
15.	Michael D. Roberts	Booker, Dr. Redemption
16.	Roger Aaron Brown	Edward Mantu, Mabuto
17.	Ryan Michael	Ray Rigel, Deegan
18.	Ramon Franco	Spider, Ramon
19.	Lance LeGault	Elliott, Sheriff "Bull" Bodine
20.	Julie Downing	Laura, Officer Walker
21.	Patrie Allen	Katherine Woodman, Marie Morrison
22.	Walter Gotell	Starkoss, Barenov
23.	Herbert Edelman	Riggins, Tubbs
24.	Malcolm Stewart	Frank Skinner, Marsh
25.	Kai Wulff	Ladysmith, Stephan Frolov, Nicolas Von Leer, Hans Visser
26.	Terry David Mulligan	Frank Rogan, Danny Barrett
27.	Milton Selzer	Otto Romburg, Izzy
28.	Allan Lysell	Walker, Wrightman, Sheriff, Dorman
29.	Larry D. Mann	Daniel Sims, Capt. Ion Cuzo
30.	Robert Donner	Vince, Wintergreen, Milt Bozer, Milt
31.	Christopher Neame	Erich Von Leer, Duncan, Quayle
32.	David Ackroyd	Knapp, Trumbo
33.	Keye Luke	Adam Chen, Prasert
34.	Blu Mankuma	Lt. Rhome, Sheriff Hubbard
35.	James Sloyan	Colter, George Fraley
36.	Frank Ferrucci	Major, Armin
37.	Keone Young	Zhao, Chung Tai Shan
38.	Vernon Wells	Catlin, Paul Donnay
39.	Richard Chaves	Enrique, Manny
40.	Tim Rossovich	Political Prisoner, Willard, Mike Desmond
41.	Madison Mason	Matt Webber, Dan Stringer, Reese
42.	Andrew Rhodes	Richardson, Lazarus
43.	Larry Dobkin	Professor Ryman, Alexander Karsoff
44.	Jerry Wasserman	Maddox, Nick Milani
45.	Don Galloway	Bob Stryke, John Collins
46.	Mitzi Kapture	Laura Bartlett, Katie
47.	Garvin Funches	Coco, Brian Jeffries
48.	Dale Wilson	Sundance, Colin Yardrow, Dennis, Erik, Crandell
49.	Time Winters	Merlin, Peugeot
50.	Michael Ensign	Professor Wycliff, Derek
51.	Beau Billingslea	Mr. Monroe, Boone
52.	James Hong	Lee Wenying, Commissioner Chu, Kuang
53.	Jackson Davies	Father Pat Lafferty, Kiley
54.	Garwin Sanford	Durst, Rafael
55.	Ned Bellamy	Remick, Larkin
56.	Henry Gibson	Pinky, Chicken Habit Customer
57.	Katey Wright	Karin Graff, Charlie Stone
58.	Martin Milner	James MacGyver, Turk
59.	Gerry Bean	Wilcox, Dick Russell
60.	Kaj-Erik Eriksen	Jacob, Tommy Wiley
61.	Linda Darlow	Doc Beatty, Connie, Principal
62.	Peter Yunker	Richard Giordano, Carlo
63.	Alex Colon	Samad, General Salazar
64.	Nana Visitor	Carol Varnay, Laura Farren
65.	Don Stroud	Kluge, Commander Hilliard
66.	Alan Fudge	Paul Webster, Jay Michaels
67.	Garry Chalk	Tony Ellis, Sgt. Harold Gray, Det. Sweeney
68.	Cuba Gooding Jr.	Billy Colton, Ray
69.	Anthony Holland	Mr. Ellard, Leo Burns, Vincent Battaglia
70.	Michael MacRae	Larson, Stams, Ghant
71.	Bruce Harwood	Juice, Willis
72.	Dana Elcar	Andy Colson, Pete Thornton

If you find errors or omissions in the table, do leave a comment.

No, I didn't compile that list manually, but rather using data from episode quides and a short Python program to analyze the data.