Kinuskikissan tervehdys - Tutorial on many piping techniques. It is in Finnish, use Google Translator. Lots of tips, uses a ziplock bag for the huge Wilton icing tip, grass tip to decorate the side of a cake.
BakingBuyer1 - very cool way of doing roses that look beyond usual roses. To do in buttercream, you would have to freeze them until ready to place on the cake. Amazing how fast he decorates that cake with perfect uniformity.