Different ones, or total? There's a couple routes I've done multiple times. But, a partial list:
Seagull Century in Maryland: 94, 95, 97, 98, 99
King's Tour of the Quabbin in Massachusetts: 2000, 01, 02, 03
Double Metric version of the Quabbin ride in: 04, 05
The Flattest Century in the East: 03, 04, 05
Tri-State Seacoast Century: 03, 04, 05 and hopefully again next month
Mt. Greylock Century: 02, 05 (because I had forgotten how obscenely hilly this ride is after three years).
Connecticut MS chapter century in 04 and 06.
Vernon to Vernon (Vernon VT to Vernon CT) in 03 and 04.
NVP century in 01, 04 and 05 (Nashoba Valley Pedalers, local bike club)
Climb to the Clouds more times then I can remember -- pretty much every year.
Cycle Across Maryland had an optional century day in 95 which I idiotically did for some reason in near 100 degree heat.
Cycle Oregon had non-optional back-to-back century days in 2002 which I had to do. One of the days was virtually all downhill though.
The big bike club in Washington DC varied their annual century every year. I did those four or five times
Ummmmm. What else? There's:
Camp Quinnebaug Century which feels like a 100 mile climb. There is no downhill in that entire ride.
Blazing Saddles Century along the Massachusetts coast.
CycleFest in Bethel, CT
Mt. Washington Century in New Hampshire
Great Mass Getaway century (MS-150 ride)
COVAC (Connecticut River Valley Century)
LAF (Lance Armstorng Foundation) Century in MA.
Great River Ride in the Berkshires.
Mad River Valley century in Vermont
Major Taylor Century in Massachusetts
Prouty Ride in New Hampshire
Harvest ride in Connecticut
Shouhegan River Ride in Massachusetts (two or three times)
CRW Spring Century in Massachusettts (three or four times)
Southern CT Cycle Club century
The White Churches of CT tour (not it's real name, but that's what it is).
So somewhere around 50 all told. I'm certainly forgetting a couple. My total started going way up ever since I moved to New England from Virginia because the summers are so much nicer (i.e., longer rides are routinely possible). My total started going up a lot more ever since I met Cheryl (my regular riding buddy who is addicted to long rides). My total is dismal this year because I just haven't been able to stay healthy this year.
Hopefully that's coming to an end and I can whip my tush into shape for one or two more long rides before it starts getting cold.
Aren't you glad you asked???