I have always been fascinated by trips about people (alone or in various "water craft") surviving the plunge over the falls. Most recently an unidentified man went over the falls and survived - possibly as part of a suicide attempt (articles here and here and here). The survivor is only the third human known to survive a trip over the falls without some sort of "safety device."
"Annie Taylor" - pictured above right - was the first human to survive the falls in a "barrel." She chose to ride in a barrel with her cat at age 63.
As a former kayaker I remember Jess Sharp's failed attempt to kayak the falls most clearly. In 1990 Sharp kayaked to his death over Niagara Falls. Sharp, from Tennessee, believe that he could survive the plunge by launching himself fast enough to clear the falls and land in the water below.
The various contraptions people build to survive the falls are also interesting.
For example, Bobby Leach's steal "barrel:"
Red Hill's contraption:
There is an equally interesting history of traversing the Niagara Gorge. This is the section of the Niagara Rive that runs below the falls.
For many years it was illegal in both the US and Canada to even enter this water. However four kayakers made the first legal descent of these rapids in 1981:
Two of the kayakers had made illegal descents in the 1970's.
The video talks about 20 foot standing waves in the gorge. I recall kayaking the New River Gorge in West Virgina in the late 1980's and kayaking through 15 foot standing waves - it was quite a ride.
Lower Keeny at low water: