Nederlands Winter Endurance Kampioenschap in Dutch, their season consists of four races at Zandvoort and one 4h race at Oschersleben. Which I consider going to.
It's on 11th December, 3rd Sunday of Advent, and probably rather cold outside

Which is why I'm asking if anyone knows about this series and what to expect?

Never heard of it TBH

Had a look at the entry lists, seems like a nice series. Cars range from Renault Clios (lots of them) to GT Porsches, Marcos Mantis, and there's a Saker in there too. Some big names as well, notably Jan Lammers and Tim and Tom Coronel.
Also Zakspeed have entered and are using the race as a testbed for their new Saleen S7-R, giving it the first public appearance

You know the racedates?

Zandvoort site doesn't mention this

29 Oct 05 - Zandvoort 500 (500 km)
11 Dec 05 - Oschersleben (4 hours)
08 Jan 06 - Nieuwjaarsrace (4 hours)
12 Feb 06 - 5 uur van Zandvoort (5 hours)
05 Mar 06 - The Final 6 (6 hours)

All at Zandvoort except round two.

Might be fun to go to, assuming it's cheap and if a fair amount of cars will be there.

Any place where I can find some more info about this? Google doesn't really help...

The first race of the season saw almost 60 cars and you pay about €10 for general admission.

You can find more news on http://www.dnrt.nl/wek or http://www.racexpress.nl

Damn, a gap of 0.03 seconds between the number 1 and 2 after 4 hours of racing

Looks like a nice grid, must convince my bro to go to Zandvoort in the blistering cold