[Dolototo]

Haven't seen any kids so far.

I think it's doable but not a lot of fun. You will have to walk from one lecture to another outside, lots of crowding in plenty of spots.

Public transport is also full.

But there are two bigger rooms (one old one new) with good talks you can always go to

[Vinnl]

I have seen a couple of kids there who themselves were super interested in FOSS. Admittedly, I'm guessing they were at least 12 years old (I'm pretty bad at guessing ages), but definitely one of the highlights of my attending last year.

[unixhero]

Fosdem sounds very bare bones and not appealing to visit.

[Dolototo]

You go there for the diversity of talks, all the open source spirit, great food and beer.

While it's definitely bare, and the weather was often shit, it's my most favorite conference