stacking advantage

[LucianoAr]

it happens a lot in our games that we have multiple instances of advantage, and it would be cool to stack them, or have an additional effect

weve been adding random modifiers to the rolls, but id like to know what other ideas you guys have

(say, advantage +2 to the roll, for a single stacked advantage)

[Kurald Galain]

For double advantage, I'd simply go with rolling three dice and picking the best. It's both faster and gives more reliable results than adding a static modifier somewhere.

[Kryx]

The RAW is that any amount of (dis)advantage cancels out any amount of the other form.
At minimum I think whichever has more should at least win (3 advantage and 1 disadvantage should be advantage).

I, like you, have also chosen to add a small bonus for each additional (dis)advantage.
I used "weak stacking" from http://www.dandwiki.com/wiki/Stacking_Advantage_(5e_Variant_Rule) and limited the maximum to a +/-5.

So if there are 5 forms of advantage and 2 forms of disadvantage it is 3 forms of advantage which is advantage with a +2.

I was considering +2, but even a +1 is significant when dealing with advantage.