Online Writing Challenges

Plotting/Ideas
National Novel Plotting Month
December National Plot Writing Month (For NaNoWriMo novels)
30 picture book ideas during November

Editing
National Novel Editing Month (March) - 50 hours of editing

Novel Writing
-General
Twelve Novel Writing Months - 50k monthly
Monthly Novel Writing
Wrimo every other month
3 Day Novel (Labor Day weekend) (must pay)
Book in a Week
National Novel Continuing Month
National Novel Publishing Year

-Month Specific
January Novel Writing Month
February Novel Writing Month
April Fools
May Novel Writing Month
May Novel Writing Month
Southern Cross Challenge (June)
Write that Damn Novel in June
June Novel Writing Month
July Novel Writing Month
August Novel Writing Month
September Novel Writing Month
September Novel Writing Month
October Novel Writing Month
National Novel Writing Month (November)
National Novel Writing Month (November) (18 and under)
add 30k to the November Novel in December
Camp Novel Writing Month (2013 in April and July)

-Genre Specific
Historical Novel Writing Month (January)
Random Genre Month (January)
Fantasy Novel Writing Month (January)
Interactive Fiction Feb 15 - Mar 15
National Noir Writing Month (August) (Dark or Mystery)
Goth Novel Writing Month (October) (Goth or Dark)
Science Fiction Writing Month (October)

Short Stories
Story a Day (December)

Poems
National Haiku Writing Month
Refrigerator Poetry Writing Month (April)
5000 line poem in May
October Poem Writing Month

Songs
See Musical Challenges

Scripts
National Play Writing Month
Script Race (monthly)

NonFiction
Write NonFiction Now
Write NonFiction Now (November)

EBook
National EBook Writing Month (November)

Letters
Letter Writing Month (February)

General
Writing Year
Million Word Year
National Blog Posting Month
SpringWrite
SummerWrite
AutumnWrite

Inactive
National Novelists Exercising Month (NaNoExMo) - Exercise 10 minutes a day in December
World Poetry Writing Month (February) - Write a poem a day in February
Script Frenzy - Write an 100 page script in April

Some of these challenges may not be active. If you find any that are not active or ones that are not on the list, let me know and I will update the list.