It's from Nuku Nuku TV, from an episode between 7-
12 (as far as I know there were only 12 eps in 
the TV series, but I've only been able to get my 
hands on the first 6).  I'd love to see exactly 
what episode it is, since I've been seeing some 
very kawaii cels popping up of Nuku Nuku in her 
PJ's from that ep in the past few months.

For those who've seen the OAV, the TV series 
tends to be a bit sillier and IMHO the character 
design for Nuku Nuku herself is a bit better (but 
Papa-san lost his cigarette).

As a side note, does anyone know where the cels 
are from Nuku Nuku DASH!????  The only ones that 
I've seen have been two that animechaos had of 
Ryunoske (one of which I own, since I prefer his 
character design in DASH!).  I'm surprised that 
I've never seen any of Nuku Nuku herself from the 
series -- if you'd seen any, you'd know: she 
looks very much like the OAV's, except with pale 
green hair.  I'm also disappointed that it's only 
been subbed up through ep 4 and no one seems 
interested in doing any more... I guess redoing 
the series as a Drama/Romance just didn't appeal 
to most people.