Counting dates within a period of time

I need a formula that counts "per hour" instead of "per day".

http://www.excelforum.com/showthread.php?t=621569

I have a simple worksheet which contains 3 columns;
A=DATE, B=TIME, C=DATE+TIME.
These columns are recognized as valid dates and times by Excel.

Each row has an entry which represents a logged "event".
The range in the DATE+TIME column can span 2 or more days.
There may be 1 to 3,000 rows on a worksheet.

I want to count the number of events that were logged each hour.
My manual inspection shows there may be anywhere from 0 to 250
events logged in any given one-hour period.

I have been successful using =SUMPRODUCT on normal data, but I
haven't been able to figure out the idiosyncracies of the dates and
24-hour clock.

Thanks in advance for any help!