I found this list, and thought it was really good:

1. Color
2. Blow Bubbles
3. Play Hide-and-Seek
4. Peek-a-Boo
5. Play Chase
6. Do Fingerplays
7. Sing a song
8. Collect rocks in a basket
9. Make an obstacle course out of cushions and/or furniture
10. Make a fort out of cushions and sheets
11. Go for a Walk
12. Make a Car out of a box
13. Read a book
14. Go to the park
15. Fingerpaint
16. Play with Clay-Dough
17. Toss Bean bags into a Bucket
18. Play the shell and pea game
19. Dance to music
20. Download games for toddlers from the Internet
21. Practice putting things in and taking things out of boxes and bags
22. Make a temporary slide out of a table leaf and your couch
23. Roll a ball back and forth on the floor
24. Scoop dirt or sand into a child’s bucket (or use a serving spoon and bowl)
25. Practice climbing by stacking boxes on top of each other (only with adult supervision)
26. Put on a puppet show
27. Go fishing with a yard stick and yarn
28. Make a Horseshoe game
29. Make a Shape Puzzle
30. Play paper basketball
31. Run through a Sprinkler
32. Play with a bucket of water and a sponge (PLEASE WATCH CHILD AT ALL TIMES!)
33. Make a Drum out of an oatmeal box
34. Play with a kazoo
35. Wash windows together
36. Bang on Pots and Pans with a spoon
37. Brush each other’s teeth
38. Play dress-up with stuffed animals and your child’s clothes
39. Stack canned or boxed food on top of each other
40. Let child stack mixing bowls inside each other
41. Make a playhouse out of a large box
42. Let child play with a sticker sheet (make sure your child doesn’t eat them!)
43. Put stickers on fingers for finger puppets
44. Play a musical instrument together- i.e.recorder, piano, etc.
45. Go on a Smelling Hunt
46. Frost Cookies
47. Plant a flower or vegetable plant together
48. Roll a tennis ball into an empty trash can or bucket
49. Draw on a mirror with dry-erase markers
50. Play hide and seek together- trying to find a stuffed animal or other object
51. Have a splash party together in the bathtub
52. Put a leash on a stuffed animal and walk around the house
53. Record each other on a tape recorder (great for scrapbooks or journals!)
54. Make and try on paper hats
55. Give a piggie back ride
56. Play "Horsie"
57. Talk into an electric fan (it distorts your voice)
58. Play tug-of-war with a blanket
59. Collect flowers (felt, artificial, real…)
60. Make a camera and go on a Safari
61. Play games with frozen juice lids
62. Disconnect your phone and pretend to make phone calls to relatives
63. Leave your phone connected and really make phone calls to relatives- let your child talk too
64. String large beads onto or along a shoelace
65. Squirt each other with squirt bottles
66. Glue shapes onto paper
67. Make sock puppets
68. Make paper puppets
69. Fill an old purse with toys
70. Use a paper towel tube as a megaphone
71. Make binoculars and go "Bird Watching" or "Stuffed Animal Watching"
72. Put snacks in different fun containers (paper sacks, empty canisters, etc.)
73. Act out a story from a book
74. Walk on a balance beam- use a 2×4 placed on the ground
75. Draw with chalk on the sidewalk
76. Sketch an outline of your child on the sidewalk or paper with chalk
77. Paint child’s palms with tempura paint and blot on paper. Makes a great card for loved ones!
78. Put lipstick on child and kiss a mirror
79. Make a puddle on cement and splash barefoot in it
80. Let child decorate and eat an open peanut butter sandwich
81. Make a toilet paper barricade for child to go under, over, or through
82. Do the Hokey Pokey
83. Make a super-hero costume out of household items
84. Do Knee-Bouncing Rhymes
85. Play "Red Light, Green Light" saying "Go" and "Stop"
86. Make a shoebox train for stuffed animals
87. Make a pillow pile to jump on (keep it clear from any hard surfaces, including walls!)
88. Make an easy puzzle with felt and velcro
89. Make bracelets or collars for stuffed animals out of pipe cleaners and jingle bells
90. Learn numbers from a deck of cards
91. Play the matching game with a deck of cards
92. Make a domino chain
93. Have a picnic in the park, backyard, or living room!
94. Play dress up in Mommy or Daddy’s clothes
95. Make a tin cup telephone and talk to each other in it
96. Make a nature collage
97. Mirror each other
98. Make a "Mummy Mommy" with toilet paper
99. Make a tape recording of short music selections and instructions to move in different ways
100. Make and walk along a toilet paper trail
101. TAKE A NAP!!