Our Mahalo-Subaru survey has mapped out large scale structures in and arounddistant clusters and the star formation activities therein since z~3 to 0.4 acrossthe peak epoch of galaxy formation in the Universe, by using the unique sets ofnarrow-band filters on Subaru wide-field instruments (Suprime-Cam and MOIRCS).It has revealed a rapid increase of integrated specific star formation ratewithin the cluster cores, which scales as steeply as (1+z)^6. A significantfraction of such star formation is hosted by red, dusty galaxies, which tendto favor the densest cores/clumps of the proto-clusters at z>2. Recently, we have conducted even deeper NB/BB imaging (Halpha emitters) on az=2.5 proto-cluster, which has discovered new populations with high sSFR at thelow mass end (~<10^9Msun). They are located significantly above the star-formingmain sequence traced by our companion deep Ly-alpha emitter survey.We will see if these are cluster-specific populations or not with the scheduledcomparably deep imaging in the general field. Finally, I will introduce an up-coming 1-sq.deg. SWIMS-18 near-infrared surveyusing 18 filters (6 narrow-bands, 9 medium-bands, and 3 broad-bands) on Subaru and TAO.