Hex__|__Binary
 0	0000
 1	0001
 2	0010
 3	0011
 4	0100
 5	0101
 6	0110
 7	0111
 8	1000
 9	1001
 A	1010
 B	1011
 C	1100
 D	1101
 E	1110
 F	1111

Hex|ASCII
41 A
42 B
43 C
44 D
45 E
46 F
47 G
48 H
49 I
4A J
4B K
4C L
4D M
4E N
4F O
50 P
51 Q
52 R
53 S
54 T
55 U
56 V
57 W
58 X
59 Y
5A Z

So to get R, you'd take 5 and 2 in binary (0110 and 0010, respectively) and put them together:  01100010=R

To get lower case letters, simply add 20 to the upper case value.  To get lower case R (72 in hex), simply add 20 to the upper case R's hex value (52).  So to type "lol" in binary, you take 6C (4C is upper case L, 4C+20=6C=lower case L), 6F (same deal), and another 6C, and mash it all together in binary:  011011000110111101101100

To memorize binary is simple.  Just remember all the hex-->binary values in your head (they do follow a pattern, but it's kinda hard to pick up on) and remember that 41-5A are letters, starting with A, and to get the lower case, you simply add 20 to it.  Simple!