It seems remiss to talk about hyped-but-failed IPOs and not include Vonage. Although Vonage is a going concern today, the company's $531 million IPO in May of 2006 was virtually a disaster - the stock fell 24% in its first two days and problems with the offering led to a class-action suit. Although Vonage flirted with bankruptcy, the company is still a going concern and generating actual operating cash flow.
Other names may also ring a bell or elicit a groan from investors with long memories. Genuity spun out as part of the Verizon and GTE merger. The company IPO'ed in June of 2000, and raised $1.9 billion. That was not nearly enough, though, as the company defaulted on its loans, went bankrupt in November of 2002 and was brought out of bankruptcy by Level 3. Proving that a good pedigree only goes so far, AMD spin-out Spansion managed to elbow Intel aside in the NOR flash market, but could not do so profitably. The company IPO'ed in December of 2005 and raised $506 million - only to go bankrupt in March of 2009 and reemerge in May of 2010.