Does Rare Candy override evolution-preventing effects such as Archeops' "Ancient Power" Ability?
Ancient Power does not allow you to use a Pokemon's attack or play a Trainer card to evolve your Benched or Active Pokemon, unless the Evolution card you would be putting into play comes from somewhere other than your hand. So Rare Candy cannot be used while Archeops' Ancient Power Ability is in effect.
Source: Noble Victories FAQ (2011-11-17), PUI Rules Team (2011-11-17), PUI Rules Team (2011-11-21)

Relevant cards

Note: All applicable cards may not be listed below.
BW10_105
BW10_85
BW5_100
DP4_102
EX13_90
EX2_88
EX9_83
HGSS2_82
POP5_7
POP8_10
SM1_129
SM2_165
SM7_142
SWSH1_180
SWSH1_180
XY5_135
BW3_67