Just keeping a track of these things for my book: "China didn't even the bubble, but...":

New A-share trading accounts opened by frenzied mainland retail investors look set to exceed 10 million for the year next week when China's stock market resumes trading after the Labor Day holidays.
Some 4.75 million new accounts were likely added in April alone, according to the latest data from the China Securities Depository and Clearing Corp.

The single-day record of 311,110 new accounts was set April 24. For the five days ended last Friday, a total of 1.48 million new accounts was recorded - a weekly record...Many mainland investors are suspected of opening more than one account - inflating the number of retail investors entering the market - nevertheless the speed of new accounts being opened over the past two months is dramatic.

It is believed the new accounts would have become active immediately. Assuming each account holder invested a conservative 20,000 yuan (HK$20,302) into the A-share market, this translates into more than 4 billion yuan pouring in each day for the past three weeks - a staggering 60 billion yuan.

A shares, available only to mainland residents, trade at a premium to their Hong Kong counterparts as China's markets are flooded with funds but short on investment options, while investors in the Hong Kong market tend to be more rational and cautious, Yip said.

For example, A shares of Jiangxi Copper (0358) closed Monday at 25.12 yuan, or a 127 percent premium over its H shares, which closed at HK$11.20. Sinopec Yizheng Chemical Fibre (1033) trades at a 300 percent premium of its A shares over its H shares.

At least you can tell your grandkids you were there during the madness.

Update: Over at Marginal Revolution, some bubbles can be good for the economy.

And Philip Bowring on China's baby steps bubble.