October is beer festival season in Shanghai (pretty much the only few weeks with good weather). Three big ones are happening this weekend:
Shanghai Oktoberfest

This is probably the closest you'll get to a proper Munich-style Oktoberfest in Shanghai. Organized by GermanEvents, a group of well-connected Germans who've been doing this for years, it's become something of an annual reunion for Shanghai's German community.

The setup is convincing: a proper Bavarian beer tent, Hofbräu beer, German food from Zeitgeist, and the kind of atmosphere that tends to get louder as the evening goes on.
It's also extremely popular. Most sessions are already sold out, although a few still have availability. The catch: tickets are sold by the table, with eight people per booking. No individual seats. So you'll need to round up seven friends.

Best for: The full Oktoberfest experience, particularly if you can get a group together.
Beerkraze

Beerkraze has been running beer festivals around Shanghai for a while now, including a particularly successful run in Jing'an. For its ninth edition, it's moving to Crystal Bridge, a newer shopping complex near Loushanguan Road Metro Station.

This one is less about Bavarian traditions and more about trying different beers. More than 100 craft beers are expected, alongside food stalls, DJs, tastings, and two outdoor stages. The festival spreads across multiple levels of the complex, so there's plenty of room to explore.

Entry is free, and advance beer packages start at 50rmb for three beers. A considerably easier commitment than booking an entire Oktoberfest table.
Best for: Craft beer fans, casual afternoon drinking, and anyone who prefers wandering between beer stands to sitting at one table.
Biyun Beer Festival

On the other side of Shanghai, Biyun is putting on a beer festival of its own, and judging by the scale of the setup, this could be a big one.
This looks more like a sprawling neighborhood festival than a traditional Oktoberfest, with a strong family focus and plenty of entertainment for children. Expect a more local crowd, although Biyun's large international community should give it a fairly mixed atmosphere.

Probably the most interesting option for families who want to make an afternoon of it, rather than just go somewhere to drink beer.
Best for: Families with kids, Pudong residents, and anyone looking for a large outdoor festival