8-10/6 Žižkovské Pivobraní with almost 30 micro and regional brewers together with food from small producers, concerts, etc. More info (in Czech) here http://www.farmarsketrziste.cz/pivobrani
15-16/6 "Festival Minipivovarů" in the Royal Gardens of Prague Castle. This one is organised by the Czech Microbrewers’ Association and will feature 50 micros from the whole country. Entry is 300CZK and you’ll get a tasting glass and off you go, to taste all you want.