ThemeForest - BluBird - 404 Error Page - RIP | 612 KB
Animated, Search Box, Simple Design, Easy to use, CSS3 Animations, Html5 Valid, CSS Valid.
DEMO:
http://themeforest.net/item/blubird-404-error-page/5307171?WT.ac=search_thumb&WT.seg_1=search_thumb&WT.z_author=CKARA