In creative mode, open chat (t) and type:
/give <playername> <BlockID> 1 <Metadata>

Example:
/give Shoeboxam 5 1 4
Crates appear in Shoeboxam's inventory.


-MCPatcher or Optifine required
-MCPatcher required to see blocks rendered correctly in inventory
-Soartex is required to see these blocks
--------------------------------

Block Listing
BlockID:Metadata Usage
---------------------------------
Block ID 5 can burn!
5:4 Crate
5:5 Wood Cubes
5:6 Timber Framing Split
5:7 Timber Framing Cross
5:8 Plank Paver
5:9 Unused
5:10 Hive
5:11 Paneling Oak


24:3 Brick Sandstone

24:4 White planks
24:5 Orange planks
24:6 Magenta planks
24:7 Light blue planks
24:8 Yellow planks
24:9 Lime Planks
24:10 Pink planks
24:11 Gray Planks
24:12 Light Gray Planks
24:13 Cyan planks
24:14 Purple planks
24:15 Blue planks

5:12 Brown planks
5:13 Green planks
5:14 Red planks
5:15 Black planks


98:4 Brick Flat
98:5 Brick Green
98:6 Basalt Paver
98:7 Brick Shiva
98:8 Brick Large
98:9 Sandstone 2x2
98:10 Ivy Wall
98:11 Mossy Round
98:12 Concrete
98:13 Limestone
98:14 Stone Paver
98:15 Rock


155:6 Gift
155:7 Shiny Glowstone
155:8 Red Tile
155:9 Blue Tile
155:10 Iron Sheet
155:11 Safe
155:12 Steel
155:13 Iron Paver
155:15 Marble



Walls:
139:2 Stone
139:3 Sandstone
139:4 Stone Brick
139:5 Clay Brick
139:6 Quartz
139:7 Oak Log
139:8 Snow
139:9 Obsidian
139:10 Hardened Clay
139:11 Blue Wool
139:12 Brick Green
139:13 Basalt Paver
139:14 Iron Block
139:15 Red Mushroom
