You need paranthesis around your OR items (the teams i assume).
"SELECT * FROM tblGame_Schedules WHERE (Home_Team = '" & Me.dropdownlist1.selectedvalue & "' OR Visiting_Team = '" & Me.dropdownlist1.selectedvalue & "') AND Year(Game_Date) = '" & Me.dropdownlist2.selectedvalue & "' ORDER By Game_Date, Game_Time"