I’m exactly 6 hectofortnights (1200 weeks) old today, and that’s not something that happens all the time. 
Happy hectofortnight! and many happy returns of the, uh, hectofortnight!
Since a fortnight is two weeks, you are now 600 fortnights old. I guess I’m confused about where the hecto- comes from.
Sorry.
Hecto means hundred.
Thank you. You know, you’d be amazed how hard it is to find appropriate greeting cards for this occasion.
Not amazed at all – this is why I had to resort to a hand-typed greeting – I went over to my favorite e-cards site and they didn’t have a freakin’ thing.