What foods or substances can overwhelm the tastebuds for 1+ hour?

I don't know why you would eat anything that would be that disgusting.

That said, I've eaten a bag of the candy 'Warheads' and killed my taste buds for days.

Seriously, I've done it a couple times, like an idiot.

You could try ice water or hot sauce, but in some cases the cure might be worse than the actual foul tasting product you must eat. Also, the both the ice water and hot sauce will only numb your taste buds for a short while.

Certain fruits have astringents in them that dry out the tongue like raw jamun berries... eating them makes your mouth quite dry to be able to taste things properly.

Hot Chillies definitely overwhelm taste buds.

The miracle berry http://en.wikipedia.org/wiki/Synsepalum_dulcificum

makes things taste sweet. (The name might sound gimmicky but this scientifically works ! )

Really sour/ cold things are other obvious ways.

Eat an onion like an apple.