Here's one I found playing around. I'd been looking for a bright yellow sunny text effect with a shadow and this works well for what I want.

I started with a black background, 16 million colors, 400x100 size.

Select white for the foreground.

Use the text tool and write your text. Do not deselect your text.

Save your selection (Selections | Save to Disk), with whatever name you want.

Go to (Image | Deformations | Motion Blur). Set the blue Intensity to 30 degrees. Blur the image four times, once to 0 degrees, once to 90 degrees, once to 180 degrees and once to 270 degrees.

Dilate the image five times. (Image | Other | Dilate)

Load the selection you saved (Selections | Load from Disk). Do not deselect.

Apply a negative image, (Colors | Negative Image).

Deselect the text, click on the magic wand tool with tolerance and feather set to to 0. Click outside the image, then invert the selection. (Selections | Invert).

Colorize the image,(Colors | Colorize). Set the Hue to 160 and Saturation to 240.

Deselect the text and apply a negative image, (Colors | Negative image) and you're done!