Thar System
1. e4 e5 2. Bd3 (bishop developed) 3. c4 (space grab) 4. Nf3 (knight out) 5. Nc3 (second knight out) 6. Be2 (bishop moved to open d3) 7. d3 (center support + bishop opens) 8. O-O (king castled, rook activated)
I was talking about opening
French Defense
The Simplest and easiest will be known as the Vienna Gambit. No longer called a 'game' or 'system'.
For me personally, I like the Queen's Gambit, Go take a look at it.