Baby Led Weaning - took up hours and hours of our day at 6 months! Of course not all 6 month old are into eating but many are, and even if they don't eat it food is a fabulous new thing to hold, prod, squish, smear, finger paint with, sniff, lick, gum and explore. It took up so much of our time I even posted about it as we did almost nothing else all day (few books, songs etc but seemed like he did nothing but eat and sleep), but then I realised that eating for a 6 month old is not like eating for an adult, at 6 months food isn't something you do between activities, it IS the activity. Great for fine motor development too.
Mum and baby groups we went to a couple of times per week too, both enjoyed those.