Once again the staunchly Sunni Kingdom of Saudi Arabia has produced a self-styled Mahdi--this in addition the half-dozen who have already staked their eschatological claims in recent months (as I analyzed in my May 14, 2011, blog on this site).   According to Emirates24/7 news (citing the Saudi daily Okaz), on Friday, July 1, 2011, "a Saudi man mounted a prayer platform at the Grand Mosque [in Mecca]...and told thousands of worshippers that he was a prophet and their saviour before he was seized by police. The 36-year-old man, identified as Sami, waited until the Muslims finished their evening prayers...mounted the podium and delivered his brief, fiery speech. 'I am Al Mehdi Al Montathar…I am a prophet sent (by God) to save and guide you'" (http://www.emirates247.com/news/region/alleged-prophet-held-at-the-grand-mosque-in-makkah-2011-07-02-1.405418). Saudi police hustled him off for the obligatory mental exam and, one might surmise, perhaps some pedagogical enhanced questioning.

Observations:
1) To reiterate briefly some of my previous analysis of this fascinating phenomenon of Mahdist claims in the heart of Wahhabi Sunnism:
a) Contra conventional (Western) wisdom on the topic, Mahdism is not just a Shi`i belief, as any examination of Islamic history demonstrates
b) Riyadh is paranoid about such movements, for two reasons:
  i) The attempt by al-Utaybi and his armed followers to overthrow the Saudi regime in 1979 was a Mahdist one
  ii) Mahdist Iran is KSA's greatest foe, and the Saudi lose sleep over the Iranians sparking such an uprising in the country, especially in the heavily-Twelver-Shi`i eastern provinces.
2) Too much can be made of this man's claim (even assuming that it was reported accurately by the authorities and/or Saudi media) that he is a "prophet." The Mahdi will of course NOT be a nabi',or "prophet" per se, in the sense of bringing a new dispensation; rather, he will be the "rightly-guided one" who renews the community of Muhammad--and, indeed, expands it to cover the whole earth.  But in the sense that Allah directly guides him, the Mahdi is prophetic.  Also, consider that reporting that quotes him as claiming to be a prophet might simply be intended to impugn him in Muslim eyes for the heterodoxy of claiming to be another prophet post-Muhammad.
3) Mahdi claims are being made not just in Saudi Arabia but throughout the Muslim world (again, peruse this site) and Mahdist expectations and prognostications are proliferating even more rapidly.  What is the reason for this? Possible explanations:
a) The belief (real or perceived) that the Islamic ummah is under attack by the "West," "Crusaders," "Zionists," and even Hindus--and the global dissemination of this belief via the Internet.
b) The approach of the Islamic year 1500 (2076 AD); there are hadiths (alleged sayings of Muhammad) that tell of a mujaddid, "renewer," of Islam who comes every century, and this doctrine has often been conflated with that of the eschatological Mahdi.
c) Iran's incessant Mahdist propaganda has increased Mahdist hopes throughout the Islamic world, including in Sunni KSA.
d) In-breeding within Islam has produced a disproportionate share of Muslims (at least vis-a-vis other societies that do not practice close-cousin marriage) who are mentally deficient and/or disturbed (on this distasteful topic, see http://richarddawkins.net/articles/631999-steve-jones-risks-political-storm-over-muslim-inbreeding ).