I've got a few helpful modifier add-ons that the community might find helpful.

Substr is a variable modifier that exposes PHP's substr function in your templates. This helped me tidy up a couple of unruly template tags.

For example, {{ day_of_week|reverse|backspace:3|reverse }} became {{ day_of_week|substr:3 }}.

The Current Datemath plugin allows you to run date addution and subtraction operations on today's date: {{ current_datemath add="10" }}

Nbsp is a variable modifier that replaces standard spaces with non-breaking spaces —  .

Finally, given a day of the week, the Next Date plugin returns the date of next occurance of that day. (That's a mouthful...)

For example, if today is March 20th, 2014, {{ next_date day="{day}" format="F jS" }} and {day} returns Monday, the tag will output March 24, 2014.

Check them out at https://github.com/than/statamic-addons