PartyGaming is the star performer after announcing a merger with Austrian rival bwin. The online gambling group said the merger would create the world's largest listed online gaming business. Elsewhere in gambling, casino and bingo hall operator Rank is in demand after a rise in profits.Connaught , the social housing group which issued a profit warning last month, rallied sharply on news that it has agreed a short-term overdraft facility and deferral of loan payments with its banks.Shares in electrical component maker Laird jumped after pre-tax profits almost doubled in the half year to June 30.Production rose in the three months to June 30 at Aquarius Platinum but the shares fell as the South African miner of the precious metal outlined safety measures that will hit future output.FTSE 250 - RisersPartyGaming (PRTY) 304.00p +18.29%Connaught (CNT) 35.20p +13.55%Laird (LRD) 122.00p +11.21%Rank Group (RNK) 118.90p +8.88%Yell Group (YELL) 26.20p +6.94%Rotork (ROR) 1,490.00p +6.73%Travis Perkins (TPK) 880.00p +6.02%Logica (LOG) 107.80p +5.69%CSR (CSR) 373.90p +5.18%Unite Group (UTG) 191.80p +4.13%FTSE 250 - FallersBrown (N.) Group (BWNG) 228.00p -2.77%Hansen Transmissions International (HSN) 72.00p -2.70%easyJet (EZJ) 393.90p -2.40%Gem Diamonds (GEMD) 216.30p -2.13%Kesa Electricals (KESA) 126.90p -1.86%Imagination Technologies (IMG) 333.70p -1.85%St. Modwen Properties (SMP) 180.00p -1.64%Dairy Crest Group (DCG) 392.00p -1.63%Aquarius Platinum Ltd. (AQP) 280.00p -1.58%Dunelm Group (DNLM) 379.80p -1.43%