I find a lot of the leveling aspects of the game to be extremely monotonous.
The cure for this, is to have a partial distraction while playing.

My mixed group will be AV'ing for 6-9 levels (depending on the toon).
They'll all be in the same pvp's until the last one dings 80.

For the most part one AV is the same as another.
Rush to Drek/Belinda, kill him/her.
Then either guard a tower/bunker, retake a tower/bunker or continue with the swarm.

I can have a dvd playing on my screen (love a 30" widescreen)...
Enough attention on it, to distract me from the fact that I've done the same BG 599 times this month.
But the game is right there in front of me, so I'll notice right away if someone comes into my tower etc.

Questing is similar.
The first couple of times, a zone was interesting.
Leveling a few single toons with my girlfriend to 80th was fun.
Then add in leveling a team to 80th.
Then the prospect of four more teams to go.
Well the quests aren't as interesting now, and will be really boring for the last team.
But a distraction while its going, helps immensely.