Arduino is an open-source electronics platform based on easy-to-use hardware and software. It's intended for anyone making interactive projects.
arXiv.org
Open access to over 300,000 e-prints in Physics, Mathematics, Computer Science and Quantitative Biology.
C++
C++ is a sophisticated, efficient and general-purpose programming language based on C.
Cite Seer
Allows users to search for computer related topics. It provides an abstract of the article and the number of times cited. Many articles are full text pdf.
Codango
This resource for web developers has reviews, guides, tutorials, and more.
Code.org
Learn to code by playing games.
The Computer Language Shootout Benchmarks
Get performance measurements and comparisons for lots of different benchmark programs and languages here.
Directory of Open Access Journals
DOAJ is a community-curated online directory that indexes and provides access to high quality, open access, peer-reviewed journals.
FreeBASIC
FreeBASIC is a free/open source (GPL), BASIC compiler for Microsoft Windows, DOS and Linux.
FOLDOC
Allows you to search for the definition of computer terms.
Geeks for Geeks
This portal has been created to provide well written, well thought and well explained solutions for selected questions.
GitHub
GitHub is a development platform that allows you to host and review code, manage projects, and build software.
Kattis
Kattis is an archive where you can find hundreds of programming problems to solve.
Project Euler
Project Euler is a series of challenging mathematical and computer programming problems that will require more than just mathematical insights to solve.
Python
Python is an interpreted, high-level, general-purpose programming language.
Science.gov
The federal government's database of science web sites by topic.
Technology Review
Published monthly by MIT examines new and emerging technology.
TechWeb Encyclopedia
Searchable database of more than 20,000 computer terms.
The WWW Virtual Library Computing and Computer Science
Provides links to a variety of topics from Artificial Intelligence to Web Design.
W3Schools Online
Contains tutorials for HTML, JavaScript, web building, and more.