sesquicentennial
vituperation
obstreperous
regurgitation
gesticulate
eviscerate
emasculate
hirsute (see The Yeti Song)
perspicaceous
olfactory (see Dead Skunk)
pluperfect
camembert
revert
undulate
polypropylene
kumquat
acrylic
(that's more than enough – sorry... got carried away!)

Here are a few "everyday"(ish) words:
screwdriver
shoelace(s)
radiator
stoplight/traffic light
cucumber
hubcap
sweatshirt
anorak (seems strangely appropriate... time to stop!)

Except that I have to mention Dick Siegel, who recently wrote "Fighting for King George", in which he used the word "misunderestimate" (brilliantly, IMO); here's an excerpt:

we fought for George's daddy
old King George the First
now we beat the drums again
this time it's George the worst

now King George is begging
"please hire me again
I'm making mincemeat of my enemies
making money for my friends

and the whole world is against us
they misunderestimate us
lord knows they ought to love us
but who cares if they hate us"