I recently kegged a 9.7% abv Belgian Tripel that was in a 10 gallon Rye Whiskey barrel for 2 months (which was almost too long). It came out really nice. I used my barrel rinser to rinse out some of the Whiskey flavor before transferring the beer into the barrel. The oak, Belgian esters, Pilsner malt and noble hops really blended well. The reaction people have when they smell it initially, without being told it's barrel aged is priceless. It's hard to stop drinking it.
Next: Tired Hands Style IPA
Fermenting: Egregious-ish, Barrel Fermented Dreg Lambic, Brett Trois Helles
Drinking: Tripel, Tired Hands Style IPA, Sterling Pale Ale, Carrot Blossom Cedar Aged Mead, RIS, Jalapeno RIS, Dusseldorf Altbier v5, Dopplebock v2, Cider, Rye Berliner Weisse, Sauerkraut Fermented Gose, Lambic, "Brett" Trois IPA, Brett Blonde, Kriek, Saison, Sour Blonde, RIS
Barrel aged: RIS, Rye Barleywine, Tripel, Wee-Heavy