Microsoft's co-founder, Paul Allen seems to be a big buff of sea cruisers. His luxury private yacht, Octopus was there at the second place in my list of top 12 high-tech luxury yachts. The latest plaything in the billionaire's playground is a fully operational 40-foot yellow submarine for which he has paid a huge sum of $12 million. With this, he has now entered the pool of 100 wealthy folks around the world who own their own submarines. Allen's craze for these gorgeous water beasts might be the reason that his net worth is only a third to that of Bill Gates. But, he is a dude with attitude. Isn't he?