I've just found out via Chessdom.com that Valeri Yandemirov passed away last year at the age of 55:
Not a household name, but he was a grandmaster with a peak rating of 2545 in 1998, and he was rated in the 2500s for most of the "noughties" as well.
The main reason why the name sticks out for me is that he was a big practitioner of two daring and sacrificial lines in the Ruy Lopez Modern Steinitz Defence: the Siesta Variation (1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 d6 5.c3 f5) and the line 5.0-0 Bg4 6.h3 h5, which some have started naming after him (notably Timothy Taylor in his book Slay the Spanish). The idea most commonly associated with Yandemirov was, after 7.d4 b5 8.Bb3 Nxd4 9.hxg4, to play 9...Nxb3 (instead of 9...hxg4 10.Ng5 Nh6, which has been shown to be insufficient for Black) 10.axb3 hxg4 11.Ng5 Qd7.
Black is currently a piece down but can generally regain the piece with ...f6 and ...fxg5 since the knight on g5 has no retreat square. The main idea is however to play ...Qf7 and ...Qh5 and try to mate White down the h-file. On the other hand this line is still theoretically dodgy because in the meantime White can smash Black on the queenside. The line was dealt quite a heavy blow in the game Gashimov-Grischuk, Baku 2008: http://www.chessgames.com/perl/chessgame?gid=1492751
Nowadays, while 4...d6 has seen some popularity at the highest levels, GMs such as Shakhriyar Mamedyarov and Nigel Short have tended to prefer 5...Bd7 over 5...Bg4, but the 5...Bg4 line has still seen a few recent GM outings, particularly in the hands of Laurent Fressinet: http://www.chessgames.com/perl/chessgame?gid=1902468
Aseev-Yandemirov, Krasnoyarsk 2003 was arguably the greatest advert for his pet line:
I have tried these lines out myself from time to time since 2009 and currently have an online game that has reached the position after 6.h3 h5. I tend to think that if it can work at GM level it must be good enough for mere mortals, even though it may be of marginal theoretical soundness.