Most half-centuries in a calendar year, in Tests and ODIs?

The Test record is 13 by Virender Sehwag in 2010 - that included eight scores between 50 and 99, and five centuries too. If you just mean half-centuries, then Keith Fletcher made nine for England in 1973 (plus two hundreds as well), and Hansie Cronje 9 for South Africa in 1998 (plus one century). In one-day internationals, Sachin Tendulkar reached 50 on 16 occasions in 1998, going on to three figures in nine of them. Sachin Tendulkar also made 13 half-centuries in 2007 (plus one century), equalling South Africa Gary Kirsten's 13 scores between 50 and 99 in 2000. In 2002, Pakistan Younis Khan made 12 fifties and never converted into  three figures, a record equalled by Sourav Ganguly and Graeme Smith in 2007.

Most over’s bowled in a single Test Series

Australian magician leg spinner Shane Warne, bowled 439.5 over’s (2639 balls) during the 1993 Ashes series in England. Mind it that was a six-Test series, the 2nd place overall is the man who bowled the most in a 5 match Test series is West Indian slow left-armer Alf Valentine, with 430 over’s at home against India in 1952-53. amazingly, Alf Valentine is also third on this list  and this time for a 4 Test rubber in England in 1950, in his debut series, Alf Valentine sent down 422.3 over’s. In 4th place for balls bowled in a series is Maurice Tate, who sent down 316 ( 8 balls over’s) in the 1924-25 Ashes series in Australia.

Wicketkeeper has made the most dismissals in a single one-day tournament.

Australian dashing wicket keeper batsman Adam Gilchrist leads the way by taking 26 catches and a stumping in 12 matches in the triangular series in 1998-99 involving England and Sri Lanka. Adam Gilchrist also holds the World Cup record, with 21 catches in South Africa in 2002-03. Whereas the record for a bilateral series is 19  set by Brendon McCullum (18 catches and a stumping) in New Zealand's  7matches home series against India,  in 2002-03.