Shabbat Shekalim ("Sabbath [of] shekels" שבת שקלים) requests each adult male Jew contribute half of a Biblical shekel for the upkeep of the Tabernacle, or mishkan (משכן).
Shabbat HaChodesh ("Sabbath [of the] month" שבת החודש) takes place on the Shabbat preceding the first of the Hebrew month of Nisan (or on the 1st of Nisan itself if it falls on Shabbat), during which Passover is celebrated.