I wasn’t a football fan as a kid but I remember watching the Steelers beat the Cowboys so that must have been either Superbowl X or XIII.
III, because of Joe Namath being all over TV
First I remember being an involved watcher… X, because of the matchup. I was 12.
You two, let’s have a beer. The rest of you kids get off my turf!
My memory on this is vague…but I’d just about have to go with Super Bowl XX. My dad, who otherwise wasn’t/isn’t an enormous football fan (basketball’s always been his de facto favorite sport), was a HUGE Chicago Bears follower at the time thanks to Refrigerator Perry and Mike Ditka, and therefore most certainly had XX on the tube. And I usually ‘watched’ (used loosely since I would be playing with my toys while marveling at whatever was on TV) most sporting events with my dad as a quite wee one (just under five years old) as long as I didn’t get on his nerves.
Super Bowl 1 I believe, though we didn’t have a TV at the time so we watched on the TV of one of the very few people in the neighborhood with a TV. I was 7 FWIW. I only recall because I didn’t get to see a lot of TV, so everything was pretty memorable or at least a pretty large event (I saw the first moon landing on the same TV and it was a similar event). It’s funny how times have changed and TVs are so ubiquitous now.
None yet.
I’m game for that beer. 
Thinking back, the first NFL game I’ve got a clear memory of is the playoff game where Bart Starr got knocked out early, and Zeke Bratkowski took over and led the Pack to the win that got them into the last pre-Super Bowl NFL championship game. But I don’t remember the Pack beating the Browns, so I guess I may not have seen any pre-Super Bowl NFL championship games.
Probably Super Bowl I, though I don’t remember. The only ones I actually watched were III, V, and XV.
Effing cheeseheads.
XVI, 1982, Bengals - 49ers. 1981 was the year Mrs. Cretin and I started noticing football and quickly became Charger likers.
The first time I knew that there was a Super Bowl going on, it was XIX in January 1985 when I was 8. It happened to be on TV at a restaurant my family was eating at, but I wasn’t really paying attention. The first one I actually watched was the following year when the Bears whipped New England’s buttocks. Unfortunately the Bears haven’t won any since then.
The early superbowl between Kansas City and Minnesota.
I had recently watched the Wizard of Oz and I was scared there was going to be a Tornado.
Super Bowl VII, the capstone of the ‘72 Dolphins’ undefeated season.
I’m from Green Bay, but, alas, a couple of years too young to remember those (I was just shy of 3 years old for Super Bowl II).
+1
ETA: I see I’m not the only +1 in the group but I didn’t count how many of us there are.
THAT was a great Chargers season. They should have gone to the Super Bowl that year, not the Bengals who went largely because the AFC Championship game was in Cincinnati on a very frozen winter day.
The Ice Bowl, that is awesome that one of the greatest games in all NFL history is the first game you remember.
Super Bowl III, January 12, 1969. The first to officially bear the name “Super Bowl”. Johnny Unitas vs. “Broadway Joe” Namath.
I remember the Brown’s Championship victory in 1964. I remember “watching” the 1957 Giants-Colts overtime game with my father and uncle. I don’t recall actually watching the game. I recall how excited they were. I was 8 then.
The first Super Bowl I watched was number I.
The first I remember being talked about was Super Bowl XXIV, though I didn’t watch it. The first one I’m sure I sat down to watch was Super Bowl XXVII. I didn’t really start routinely watching football until about the 1995 season. I was really more of a baseball fan as a kid with little interest in watching football. Playing touch football, sure, but not watching.