Hachu, I'll let others here cite instances that serve to demonstrate that the definition of rape has been so watered down as to be an amorphous concept.
However, on another related note -- accusations of rape have been shown to include huge numbers of false allegations.
According to a nine-year study conducted by former Purdue sociologist Eugene J. Kanin, in over 40 percent of the cases reviewed, the complainants eventually admitted that no rape had occurred (Archives of Sexual Behavior, Vol. 23, No. 1, 1994). Kanin also studied rape allegations in two large Midwestern universities and found that 50 percent of the allegations were recanted by the accuser.
Kanin found that most of the false accusers were motivated by a need for an alibi or a desire for revenge. Kanin was once well known and lauded by the feminist movement for his groundbreaking research on male sexual aggression. His studies on false rape accusations, however, received very little attention.
Kanin's findings are hardly unique. In 1985 the Air Force conducted a study of 556 rape accusations. Over one quarter of the accusers admitted, either just before they took a lie detector test of after they had failed it, that no rape occurred. A further investigation by independent reviewers found that 60 percent of the original rape allegations were false.
Kamin's study
http://www.menweb.org/throop/falsereport/kanin.html (revealing 41% of rape allegations examined in his study to be fraudulent) is chilling and compelling. The U.S. Air Force study which found that 60% of the rape allegations to be false --not unfounded -- but false! ... is even more disturbing.
This study was conducted and overseen by Dr. Charles P McDowell, Ph.D., M.P.A., M.L.S., Supervisory Special Agent, U.S. Air Force, Office of Special Investigations; and documented here:
"False Allegations," Forensic Science Digest, vol. 11, no. 4, December 1985, p.64. The Digest is a publication of the U.S. Air Force Office of Special Investigations, Washington, D.C.
More research is needed in this area, however, the only thing we know for sure is that false allegations are not a rarity.
This topic is covered in Warren Farrell's book, The Myth of Male Power, pp. 309-343.